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1

The Effects of Additional Action Observational Training for Functional Electrical Stimulation Treatment on Weight Bearing, Stability and Gait Velocity of Hemiplegic Patients  

PubMed Central

[Purpose] The purpose of this study was to evaluate the functional effects of additional action observational training for functional electrical stimulation treatment on weight bearing, stability and gait velocity of hemiplegic patients. [Subjects and Methods] Twenty subjects were randomized into two groups. Subjects more than six months post-stroke participated. Balance and gait velocity were measured at the baseline, and after six weeks of treatment. Both groups received functional electrical stimulation treatment. The experimental group additionally received action observational training. The paired t-test was used to analyze differences in the outcome measures between before and after the intervention. The difference between the groups was compared using the independent t-test. [Results] The experimental group showed significant increases in weight bearing (anterior·posterior, right·left) on the affected side, stability index and gait velocity. The control group showed only a significant increase in anterior·posterior weight bearing on the affected side. Moreover, according to the comparison of training effects between in the two groups, the variables of anterior·posterior weight bearing, stability index and gait velocity revealed a statistically significant difference. [Conclusion] Additional action observational training for functional electrical stimulation treatment should be considered as a therapeutic method in physical therapy for the improvement of weight bearing, stability index and gait velocity of hemiplegic patients. PMID:24259939

Park, Chang-Sik; Kang, Kwon-Young

2013-01-01

2

Complications of unilateral weight bearing.  

PubMed

The most common and significant complication of excessive unilateral weight bearing in adult horses is support limb laminitis. Young horses with unilateral lameness problems develop support limb laminitis infrequently compared with adult horses. PMID:19203705

Baxter, Gary M; Morrison, Scott

2008-12-01

3

Immediate weight bearing following modified lapidus arthrodesis.  

PubMed

First metatarsocuneiform arthrodesis (Lapidus procedure) can provide powerful correction of mild to moderate hypermobile or severe hallux valgus, although a period of non-weight bearing may be necessary. The purpose of this retrospective investigation was to compare patients who underwent a modified Lapidus arthrodesis with 2 screws plus an additional "neutralization" Kirschner-wire with immediate partial weight-bearing in a removable boot, with a control group without the Kirschner-wire who were non-weight bearing for 6 weeks in a short leg cast. A total of 41 consecutive patients from January 2004 to January 2007 were included in this comparative cohort study. There were no significant radiographic changes between immediate and final 6-month postoperative radiographs in regard to first intermetatarsal angle (degree) and first ray elevation measurements (first to second metatarsal head elevation [mm] and Seiberg index [mm]) within groups (P = .49, .47, and .54, and 95% confidence intervals of [-2.1, 1.2], [-0.32, 2.03], and [-0.82, 0.44], respectively) or between groups (P = .259, .67, and .083, and 95% confidence intervals of [-4.2, 1.2], [-1.39, 0.91], and [-1.77, 0.12], respectively), as computed with paired 2-sample t tests. Stratified Mantel-Haenszel analyses revealed both groups to be comparable relative to severity of deformity, gender, age, smoking history, perioperative immunosuppressant use, and other comorbidities. No nonunions or malunions where observed in either group. The use of a temporary Kirschner-wire as a third point of fixation may enable immediate protected weight bearing, by minimizing load placed on the crossed lag screw construct, in patients undergoing modified Lapidus arthrodesis. PMID:20638304

Basile, Philip; Cook, Emily A; Cook, Jeremy J

2010-01-01

4

Gait training with partial body weight support during overground walking for individuals with chronic stroke: a pilot study  

PubMed Central

Background It is not yet established if the use of body weight support (BWS) systems for gait training is effective per se or if it is the combination of BWS and treadmill that improves the locomotion of individuals with gait impairment. This study investigated the effects of gait training on ground level with partial BWS in individuals with stroke during overground walking with no BWS. Methods Twelve individuals with chronic stroke (53.17 ± 7.52 years old) participated of a gait training program with BWS during overground walking, and were evaluated before and after the gait training period. In both evaluations, individuals were videotaped walking at a self-selected comfortable speed with no BWS. Measurements were obtained for mean walking speed, step length, stride length and speed, toe-clearance, durations of total double stance and single-limb support, and minimum and maximum foot, shank, thigh, and trunk segmental angles. Results After gait training, individuals walked faster, with symmetrical steps, longer and faster strides, and increased toe-clearance. Also, they displayed increased rotation of foot, shank, thigh, and trunk segmental angles on both sides of the body. However, the duration of single-limb support remained asymmetrical between each side of the body after gait training. Conclusions Gait training individuals with chronic stroke with BWS during overground walking improved walking in terms of temporal-spatial parameters and segmental angles. This training strategy might be adopted as a safe, specific and promising strategy for gait rehabilitation after stroke. PMID:21864373

2011-01-01

5

The Combined Effects of Body Weight Support and Gait Speed on Gait Related Muscle Activity: A Comparison between Walking in the Lokomat Exoskeleton and Regular Treadmill Walking  

PubMed Central

Background For the development of specialized training protocols for robot assisted gait training, it is important to understand how the use of exoskeletons alters locomotor task demands, and how the nature and magnitude of these changes depend on training parameters. Therefore, the present study assessed the combined effects of gait speed and body weight support (BWS) on muscle activity, and compared these between treadmill walking and walking in the Lokomat exoskeleton. Methods Ten healthy participants walked on a treadmill and in the Lokomat, with varying levels of BWS (0% and 50% of the participants’ body weight) and gait speed (0.8, 1.8, and 2.8 km/h), while temporal step characteristics and muscle activity from Erector Spinae, Gluteus Medius, Vastus Lateralis, Biceps Femoris, Gastrocnemius Medialis, and Tibialis Anterior muscles were recorded. Results The temporal structure of the stepping pattern was altered when participants walked in the Lokomat or when BWS was provided (i.e. the relative duration of the double support phase was reduced, and the single support phase prolonged), but these differences normalized as gait speed increased. Alternations in muscle activity were characterized by complex interactions between walking conditions and training parameters: Differences between treadmill walking and walking in the exoskeleton were most prominent at low gait speeds, and speed effects were attenuated when BWS was provided. Conclusion Walking in the Lokomat exoskeleton without movement guidance alters the temporal step regulation and the neuromuscular control of walking, although the nature and magnitude of these effects depend on complex interactions with gait speed and BWS. If normative neuromuscular control of gait is targeted during training, it is recommended that very low speeds and high levels of BWS should be avoided when possible. PMID:25226302

Van Kammen, Klaske; Boonstra, Annemarijke; Reinders-Messelink, Heleen; den Otter, Rob

2014-01-01

6

Design of a mechanical system in gait rehabilitation with progressive addition of weight  

NASA Astrophysics Data System (ADS)

In this paper we designed and developed a mechanical device for gait rehabilitation based on the application of "partial body weight reduction therapy". An evaluation of the characteristics of devices based on this therapy currently available on the market was carried out obtaining information of the different mechanisms used in it. The device was designed to adapt to different height and weight of patients and to be used with additional equipment in gait rehabilitation, for example, treadmills, elliptical trainers and vertical scalers. It was envisaged to be used by patients with asymmetry in the lower extremities capabilities. We developed a stable structure in steel ASTM A36 which does not depend on the building conditions of the installation site. RamAdvanse software was used to calculate structural stability. A winch with automatic brake mechanism was used to raise/lower the patient, who was tied to a comfortable harness which provided safety to the patient and therapist. It was possible to quantify precisely, using counterweights, the weight borne by the patient during therapy. We obtained a small-sized and ergonomic low-cost prototype, with similar features to those currently considered cutting-edge devices.

Braidot, Ariel A. A.; Aleman, Guillermo L.

2011-12-01

7

Image based weighted center of proximity versus directly measured knee contact location during simulated gait.  

PubMed

To understand the mechanical consequences of knee injury requires a detailed analysis of the effect of that injury on joint contact mechanics during activities of daily living. Three-dimensional (3D) knee joint geometric models have been combined with knee joint kinematics to dynamically estimate the location of joint contact during physiological activities-using a weighted center of proximity (WCoP) method. However, the relationship between the estimated WCoP and the actual location of contact has not been defined. The objective of this study was to assess the relationship between knee joint contact location as estimated using the image-based WCoP method, and a directly measured weighted center of contact (WCoC) method during simulated walking. To achieve this goal, we created knee specific models of six human cadaveric knees from magnetic resonance imaging. All knees were then subjected to physiological loads on a knee simulator intended to mimic gait. Knee joint motion was captured using a motion capture system. Knee joint contact stresses were synchronously recorded using a thin electronic sensor throughout gait, and used to compute WCoC for the medial and lateral plateaus of each knee. WCoP was calculated by combining knee kinematics with the MRI-based knee specific model. Both metrics were compared throughout gait using linear regression. The anteroposterior (AP) location of WCoP was significantly correlated with that of WCoC on both tibial plateaus in all specimens (p<0.01, 95% confidence interval of Pearson?s coefficient r>0), but the correlation was not significant in the mediolateral (ML) direction for 4/6 knees (p>0.05). Our study demonstrates that while the location of joint contact obtained from 3D knee joint contact model, using the WCoP method, is significantly correlated with the location of actual contact stresses in the AP direction, that relationship is less certain in the ML direction. PMID:24837219

Wang, Hongsheng; Chen, Tony; Koff, Matthew F; Hutchinson, Ian D; Gilbert, Susannah; Choi, Dan; Warren, Russell F; Rodeo, Scott A; Maher, Suzanne A

2014-07-18

8

Effects of backpack weight on posture, gait patterns and ground reaction forces of male children with obesity during stair descent.  

PubMed

This study investigates the effects of backpack weight on posture, gait pattern, and ground reaction forces for children with obesity in an attempt to define a safe backpack weight limit for them. A total of 16 obese (11.19 ± 0.66 years of age) and 21 normal body weight (11.13 ± 0.69 years of age) schoolboys were recruited. Two force plates and two video cameras were used. Multivariate analysis of variance with repeated measures was employed. Obese children showed increased trunk and head forward inclination angle, gait cycle duration and stance phase, decreased swing phase, and increased ground reaction force in the medial-lateral and anterior-posterior directions when compared with male children with a normal body weight. The changes were observed even with an empty backpack in comparison with normal body weight children and a 15% increase in backpack weight led to further instability and damage on their already strained bodies. PMID:24650337

Song, Qipeng; Yu, Bing; Zhang, Cui; Sun, Wei; Mao, Dewei

2014-01-01

9

Weight, Rather Than Obesity Distribution, Explains Peak External Knee Adduction Moment During Level Gait  

PubMed Central

Objective To determine whether a lower-body obesity pattern increases estimated forces on the medial compartment of the knee joint. Design Cross-sectional clinical biomechanical study. Results Nineteen normal weight (body mass index, 22.8 ± 1.8 kg/m2), 20 centrally obese (body mass index, 35.0 ± 4.0 kg/m2 and waist-hip ratio ?0.85 for women; ?0.95 for men), and 20 lower-body obese (body mass index, 36.4 ± 5.4 kg/m2) adults aged 37–55 yrs and without knee pain were recruited. There were no intergroup differences for age. Weight did not differ between obese groups, but thigh girth differed between groups (P < 0.0001). In univariate analysis, both obesity group and thigh girth were significantly related to peak external knee adduction moment in mid-stance phase. However, in multivariate analysis after adjusting for weight, no statistically significant differences persisted using either obesity distribution or thigh girth as predictors. Weight was a significant predictor of external knee adduction moment, explaining 33% (P < 0.0001) of variance in external knee adduction moment for level gait. Conclusions These data do not support a significant difference in knee medial compartment loading based on obesity distribution, but do support greater torque with higher weight. This suggests that the mechanism of obesity increasing risk for knee osteoarthritis may not be related to obesity distribution. PMID:19847127

Segal, Neil A.; Yack, H. John; Khole, Priyanka

2010-01-01

10

Using Gait as a Biometric, via Phase-weighted Magnitude Spectra  

Microsoft Academic Search

Abstract. Gait is a ,biometric which ,is subject ,to increasing ,interest. Current approaches,include modelling ,gait as a ,spatio-temporal sequence ,and ,as an articulated model. By considering legs only, gait can be considered to be the motion,of interlinked pendula. We describe how,the Hough transform is used to extract the lines which represent legs in sequences,of video,images. The change in inclination of

David Cunado; Mark S. Nixon; John N. Carter

1997-01-01

11

Differences in Patellofemoral Kinematics between Weight-Bearing and Non-Weight-Bearing Conditions in Patients with Patellofemoral Pain  

E-print Network

, non-weight-bearing. We compared patellofemoral kinematics measured from the images. The patella than those of the non-maltrackers. In subjects with excessive lateral patellar translation, the patella and 308 (p ¼ 0.001). However, in subjects with normal patellar translation, the patella translated more

Delp, Scott

12

Determinants of bone density among athletes engaged in weight-bearing and non-weight-bearing activity  

NASA Technical Reports Server (NTRS)

The effect of weight bearing activity on the bone density was investigated in athletes by comparing the measures of bone density of athletes engaged in weight-training programs with those of polo players and nonexercising subjects. All subjects had measurements of spinal trabecular and integral bone density by quantitative tomography, as well as determinations of hip bone density by dual photon absorptiometry. Results confirmed previous findings by Block et al. (1987) of significantly greater bone density among highly trained athletes compared with nonexercising subjects of similar age. Results also indicated that athletes engaged in non-weight-bearing forms of rigorous exercise had greater levels of bone density. However, as the participants in this study were exceptional athletes, engaged in a strenuous sport with both aerobic and heavy resistance components, a confirmation of these data is needed, using larger samples of individuals.

Block, Jon E.; Friedlander, Anne L.; Brooks, George A.; Steiger, Peter; Stubbs, Harrison A.

1989-01-01

13

Eccentric exercise training as a countermeasure to non-weight-bearing soleus muscle atrophy  

NASA Technical Reports Server (NTRS)

This investigation tested whether eccentric resistance training could prevent soleus muscle atrophy during non-weight bearing. Adult female rats were randomly assigned to either weight bearing +/- intramuscular electrodes or non-weight bearing +/- intramuscular electrodes groups. Electrically stimulated maximal eccentric contractions were performed on anesthetized animals at 48-h intervals during the 10-day experiment. Non-weight bearing significantly reduced soleus muscle wet weight (28-31 percent) and noncollagenous protein content (30-31 percent) compared with controls. Eccentric exercise training during non-weight bearing attenuated but did not prevent the loss of soleus muscle wet weight and noncollagenous protein by 77 and 44 percent, respectively. The potential of eccentric exercise training as an effective and highly efficient counter-measure to non-weight-bearing atrophy is demonstrated in the 44 percent attenuation of soleus muscle noncollagenous protein loss by eccentric exercise during only 0.035 percent of the total non-weight-bearing time period.

Kirby, Christopher R.; Ryan, Mirelle J.; Booth, Frank W.

1992-01-01

14

Method for estimating maximum permissible load weight for Japanese native horses using accelerometer-based gait analysis.  

PubMed

The aim of this study was to establish a method for estimating loading capacity for Japanese native horses by gait analysis using an accelerometer. Six mares of Japanese native horses were used. The acceleration of each horse was recorded during walking and trotting along a straight course at a sampling frequency of 200?Hz. Each horse performed 12 tests: one test with a loaded weight of 80?kg (First 80?kg) followed by 10 tests with random loaded weights between 85?kg and 130?kg and a final test with a loaded weight of 80?kg again. The time series of acceleration was subjected to fast Fourier transformation, and the autocorrelation coefficient was calculated. The first two peaks of the autocorrelation were defined as symmetry and regularity of the gait. At trot, symmetries in the 100, 110, and 125?kg tests were significantly lower than that in First 80?kg (P?weight is less than 100?kg, which is 29% of the body weight of Japanese native horses. Our method is a widely applicable and welfare-friendly method for estimating maximum permissible load weights of horses. PMID:23302086

Matsuura, Akihiro; Irimajiri, Mami; Matsuzaki, Kunihiro; Hiraguri, Yuko; Nakanowatari, Toshihiko; Yamazaki, Atusi; Hodate, Koichi

2013-01-01

15

Measuring polyethylene wear in total knee arthroplasty by RSA: differences between weight-bearing and non-weight-bearing positioning.  

PubMed

Measuring the minimum-joint-space-width (mJSW) in total knee arthroplasty (TKA) in Roentgen stereophotogrammetric analysis (RSA) provides valuable information on polyethylene wear, a leading cause for TKA failure. Most existing studies use non-weight-bearing (NWB) patient positioning. The latter may compromise mJSW measurements due to knee laxity with subsequent non-contact between the TKA components. We investigated the difference in mJSW between weight-bearing (WB) and NWB images and the association with mediolateral (ML) knee stability. At one-year follow-up, 23 TKAs were included from an ongoing RSA study, and ML stability was evaluated. For each examination, the mJSW and femoral-tibial contact locations were measured. A linear regression model was used to analyze the association between the mJSW difference (NWB-WB) with the ML stability and contact locations. The mean mJSW difference was 0.28?mm medially and 0.20?mm laterally. Four TKAs had medium (5-9°) and 19 TKAs had high (<5°) ML stability. A higher mJSW difference was found for TKAs with medium stability (0.36?mm, P?=?0.01). In conclusion, mJSW measurements in existing (NWB) RSA studies are influenced by knee laxity, but may still provide information on wear progression based on TKA with high ML stability. A direct comparison of mJSW measurements from WB and NWB data is not possible. PMID:24395396

van Ijsseldijk, Emiel A; Valstar, Edward R; Stoel, Berend C; de Ridder, Ruud; Nelissen, Rob G H H; Kaptein, Bart L

2014-04-01

16

Weight bearing does not contribute to the development of osteonecrosis of the femoral head  

PubMed Central

The hip joint is one of the major structures in the human body and the resultant force acting through the hip joint is 300% of body weight. Therefore, weight bearing, as a cause of ischaemia, may contribute to the development of non-traumatic osteonecrosis of the femoral head (ONFH). However, it remains unclear whether weight bearing is related to the development of non-traumatic ONFH. Therefore the aim of this study was to clarify the role of weight bearing in the development of non-traumatic ONFH. Non-weight-bearing (NWB) rats were tail suspended to prevent any weight coming to bear on the hindlimbs from day 1 to the time of sacrifice. The weight-bearing (WB) group rats were also housed individually, although without tail suspension. All rats were injected with lipopolysaccharide and methylprednisolone to promote the development of non-traumatic ONFH. All animals were sacrificed three weeks after the final methylprednisolone injection. Histopathological analysis was performed. Osteonecrosis of the femoral head was observed not only in the NWB but also in the WB rats; however, no osteonecrosis of the humeral head was observed in either group. We confirmed that non-traumatic ONFH developed in NWB rats, suggesting that weight bearing does not contribute to the development of non-traumatic ONFH in rats. PMID:23075001

Okazaki, Shunichiro; Nagoya, Satoshi; Tateda, Kenji; Katada, Ryuichi; Mizuo, Keisuke; Watanabe, Satoshi; Yamashita, Toshihiko; Matsumoto, Hiroshi

2012-01-01

17

Correlation of psychomotor findings and the ability to partially weight bear  

PubMed Central

Background Partial weight bearing is thought to avoid excessive loading that may interfere with the healing process after surgery of the pelvis or the lower extremity. The object of this study was to investigate the relationship between the ability to partially weight bear and the patient's psychomotor skills and an additional evaluation of the possibility to predict this ability with a standardized psychomotor test. Methods 50 patients with a prescribed partial weight bearing at a target load of 15 kg following surgery were verbally instructed by a physical therapist. After the instruction and sufficient training with the physical therapist vertical ground reaction forces using matrix insoles were measured while walking with forearm crutches. Additionally, psychomotor skills were tested with the Motorische Leistungsserie (MLS). To test for correlations Spearman's Rank correlation was used. For further comparison of the two groups a Mann-Withney test was performed using Bonferroni correction. Results The patient's age and body weight significantly correlated with the ability to partially weight bear at a 15 kg target load. There were significant correlations between several subtests of the MLS and ground reaction forces measured while walking with crutches. Patients that were able to correctly perform partial weight bearing showed significant better psychomotor skills especially for those subtests where both hands had to be coordinated simultaneously. Conclusions The ability to partially weight bear is associated with psychomotor skills. The MLS seems to be a tool that helps predicting the ability to keep within the prescribed load limits. PMID:22330655

2012-01-01

18

Weight-bearing shifts of hemiparetic and healthy adults upon stepping on stairs of various heights  

Microsoft Academic Search

Objective: To examine and compare the effect of stepping on stairs of various heights on lower extremity weight bearing in hemiparetic patients.Setting: Flieman Geriatric Rehabilitation Hospital, Haifa, Israel.Subjects: Fifteen ambulatory hemiparetic patients following an acute cerebrovascular accident, and 16 age-matched healthy controls.Interventions: Each subject was tested twice on two consecutive days in five weight-bearing positions which included level stance and

Yocheved Laufer; Ruth Dickstein; Sarit Resnik; Emanuel Marcovitz

2000-01-01

19

Simultaneous bilateral opening-wedge high tibial osteotomy with early full weight-bearing exercise  

Microsoft Academic Search

Simultaneous bilateral opening-wedge high tibial osteotomies (OWHTOs), using the TomoFix fixation device and artificial bone\\u000a wedges (?-TCP) were performed on 20 knees of 10 patients with an average age of 67 years (range 53–75) at the time of the\\u000a operation. We established an early weight-bearing exercise program during which patients were permitted partial weight-bearing\\u000a exercise 1 week after osteotomy, with all patients

Ryohei Takeuchi; Masato Aratake; Haruhiko Bito; Izumi Saito; Ken Kumagai; Hiroyuki Ishikawa; Yasushi Akamatsu; Yohei Sasaki; Tomoyuki Saito

2008-01-01

20

Haptic biofeedback for improving compliance with lower-extremity partial weight bearing.  

PubMed

After lower-extremity orthopedic trauma and surgery, patients are often advised to restrict weight bearing on the affected limb. Conventional training methods are not effective at enabling patients to comply with recommendations for partial weight bearing. The current study assessed a novel method of using real-time haptic (vibratory/vibrotactile) biofeedback to improve compliance with instructions for partial weight bearing. Thirty healthy, asymptomatic participants were randomized into 1 of 3 groups: verbal instruction, bathroom scale training, and haptic biofeedback. Participants were instructed to restrict lower-extremity weight bearing in a walking boot with crutches to 25 lb, with an acceptable range of 15 to 35 lb. A custom weight bearing sensor and biofeedback system was attached to all participants, but only those in the haptic biofeedback group were given a vibrotactile signal if they exceeded the acceptable range. Weight bearing in all groups was measured with a separate validated commercial system. The verbal instruction group bore an average of 60.3±30.5 lb (mean±standard deviation). The bathroom scale group averaged 43.8±17.2 lb, whereas the haptic biofeedback group averaged 22.4±9.1 lb (P<.05). As a percentage of body weight, the verbal instruction group averaged 40.2±19.3%, the bathroom scale group averaged 32.5±16.9%, and the haptic biofeedback group averaged 14.5±6.3% (P<.05). In this initial evaluation of the use of haptic biofeedback to improve compliance with lower-extremity partial weight bearing, haptic biofeedback was superior to conventional physical therapy methods. Further studies in patients with clinical orthopedic trauma are warranted. PMID:25361376

Fu, Michael C; DeLuke, Levi; Buerba, Rafael A; Fan, Richard E; Zheng, Ying Jean; Leslie, Michael P; Baumgaertner, Michael R; Grauer, Jonathan N

2014-11-01

21

IMPROVING WEIGHT BEARING ASYMMETRY IN UNILATERAL LOWER LIMB AMPUTEES BY USE OF AN INSOLE PRESSURE SENSOR-BASED  

E-print Network

69 IMPROVING WEIGHT BEARING ASYMMETRY IN UNILATERAL LOWER LIMB AMPUTEES BY USE OF AN INSOLE asymmetry with more weight on the non-affected limb (e.g. [1]). Over the long term, asymmetric weight sensor-based electro-tactile biofeedback system in improving weight bearing asymmetry in lower limb

Payan, Yohan

22

Weight-Bearing Locomotion in the Developing Opossum, Monodelphis domestica following Spinal Transection: Remodeling of Neuronal Circuits Caudal to Lesion  

PubMed Central

Complete spinal transection in the mature nervous system is typically followed by minimal axonal repair, extensive motor paralysis and loss of sensory functions caudal to the injury. In contrast, the immature nervous system has greater capacity for repair, a phenomenon sometimes called the infant lesion effect. This study investigates spinal injuries early in development using the marsupial opossum Monodelphis domestica whose young are born very immature, allowing access to developmental stages only accessible in utero in eutherian mammals. Spinal cords of Monodelphis pups were completely transected in the lower thoracic region, T10, on postnatal-day (P)7 or P28 and the animals grew to adulthood. In P7-injured animals regrown supraspinal and propriospinal axons through the injury site were demonstrated using retrograde axonal labelling. These animals recovered near-normal coordinated overground locomotion, but with altered gait characteristics including foot placement phase lags. In P28-injured animals no axonal regrowth through the injury site could be demonstrated yet they were able to perform weight-supporting hindlimb stepping overground and on the treadmill. When placed in an environment of reduced sensory feedback (swimming) P7-injured animals swam using their hindlimbs, suggesting that the axons that grew across the lesion made functional connections; P28-injured animals swam using their forelimbs only, suggesting that their overground hindlimb movements were reflex-dependent and thus likely to be generated locally in the lumbar spinal cord. Modifications to propriospinal circuitry in P7- and P28-injured opossums were demonstrated by changes in the number of fluorescently labelled neurons detected in the lumbar cord following tracer studies and changes in the balance of excitatory, inhibitory and neuromodulatory neurotransmitter receptors’ gene expression shown by qRT-PCR. These results are discussed in the context of studies indicating that although following injury the isolated segment of the spinal cord retains some capability of rhythmic movement the mechanisms involved in weight-bearing locomotion are distinct. PMID:23951105

Wheaton, Benjamin J.; Noor, Natassya M.; Whish, Sophie C.; Truettner, Jessie S.; Dietrich, W. Dalton; Zhang, Moses; Crack, Peter J.; Dziegielewska, Katarzyna M.; Saunders, Norman R.

2013-01-01

23

Cross-Sectional Study of Weight-Bearing Activity on Proximal Femur Bone Mineral Density  

Microsoft Academic Search

.   In this cross-sectional study we investigated the effect of compressive and tensile forces applied on the proximal femur\\u000a during weight-bearing activities. Ninety-seven men (29.9 ± 1.7 years) were divided into two groups: 69 exercisers who had\\u000a practiced regular high-impact weight-bearing activities for at least 5 years and 28 controls who had been sedentary for at\\u000a least 5 years. The

M. A. Mayoux-Benhamou; J. F. Leyge; C. Roux; M. Revel

1999-01-01

24

Modulation of Ankle Muscle Postural Reflexes in Stroke: Influence of Weight-bearing Load  

PubMed Central

Objective Given the known sensorimotor deficits and asymmetric weight-bearing posture in stroke, the aim of this study was to determine whether stroke affects the modulation of standing postural reflexes with varying weight-bearing load. Methods Ten individuals with chronic stroke and 10 healthy older adult controls were exposed to unexpected forward and backward platform translations while standing. Three different stance conditions were imposed: increased weight-bearing load, decreased weight-bearing load, and self-selected stance. Surface EMG from bilateral ankle dorsiflexors (tibialis anterior) and extensors (gastrocnemius) were recorded and the magnitude of background muscle activity (prior to the platform translation) and postural reflex onset latency and magnitude (75 ms following reflex onset) were determined. Results Load modulation of ankle extensors was found in controls and individuals with stroke. Although controls demonstrated modulation of ankle dorsiflexors to different loads, individuals with stroke did not show this modulation. Further, load did not change the onset latency of postural reflexes of the individuals with stroke. Conclusion The delayed paretic muscle onset latencies in conjunction with impaired modulation of ankle dorsiflexor postural reflexes may contribute to the instability and frequent falls observed among individuals with stroke. Significance The results provide some insight into standing postural reflexes following stroke. PMID:15546787

Marigold, Daniel S.; Eng, Janice J.; Inglis, J. Timothy

2011-01-01

25

Weight bearing after arthrodesis of the first metatarsophalangeal joint. A randomized study of 61 cases.  

PubMed

We performed a prospective randomized study of 61 cases of arthrodesis of the first metatarsophalangeal joint in 56 patients. In the first group, full weight bearing was allowed after 2-4 days and in the second group at 4 weeks. Radiographic union of the arthrodesis in the two groups did not differ. PMID:1767644

Lampe, H I; Fontijne, P; van Linge, B

1991-12-01

26

Osteoporosis Prevention Among Young Women: Psychosocial Models of Calcium Consumption and Weight-Bearing Exercise  

Microsoft Academic Search

Objective: To examine the putative determinants of two osteoporosis-preventive behaviors, calcium consumption and weight-bearing exercise, in 2 samples of young women (Sample 1, n = 202; Sample 2, n = 209). A common psychosocial model of both behaviors, comprising the health belief model and augmented with constructs drawn from social cognitive theory and the theory of planned behavior, was developed,

Sarah J. Schmiege; Leona S. Aiken; Jennifer L. Sander; Mary A. Gerend

2007-01-01

27

Osteoporosis Knowledge, Calcium Intake, and Weight-Bearing Physical Activity in Three Age Groups of Women.  

ERIC Educational Resources Information Center

Determined the extent and integration of osteoporosis knowledge in three age groups of women, comparing knowledge to calcium intake and weight bearing physical activity (WBPA). Overall calcium intake was relatively high. There were no differences in knowledge, calcium intake, or WBPA by age, nor did knowledge predict calcium intake and WBPA. None…

Terrio, Kate; Auld, Garry W.

2002-01-01

28

A RELATIONSHIP BETWEEN CIRCUMFERENCE AND WEIGHT IN TREES AND ITS BEARING ON BRANCHING ANGLES  

PubMed Central

Observation reveals a linear relationship between the logarithm of the circumference of a tree, branch, or leaf stem, and the logarithm of the weight of the tree, branch, or leaf. The bearing of this on the angles of branching in trees is discussed. PMID:19872356

Murray, Cecil D.

1927-01-01

29

EMG Activity of the Abductor Hallucis Muscle during Foot Arch Exercises Using Different Weight Bearing Postures  

PubMed Central

[Purpose] This study examined the effects of different weight-bearing postures on the activation of the abductor hallucis muscle during foot-arch exercises. [Subjects] The study recruited 11 healthy volunteers who were pain-free, had no history of foot or ankle surgery, and were able to maintain a standing posture. [Methods] The subjects performed short-foot and toe-spreading exercises while sitting and standing. [Results] The abductor hallucis muscle activation in the toe-spreading exercise was significantly greater when standing than in sitting, while that in the short-foot exercise did not differ significantly between the two postures. [Conclusion] The results of this study suggests that a weight bearing posture such as standing is the most effective method of increasing the EMG activity of abductor hallucis muscle in the toe-spreading exercise. PMID:25364132

Goo, Young-Mi; Heo, Hyo-Jin; An, Duk-Hyun

2014-01-01

30

Recovery of lower limb function following 6 weeks of non-weight bearing  

NASA Astrophysics Data System (ADS)

Skeletal muscle weakness and atrophy occur following an extended period of decreased use, including space flight and limb unloading. It is also likely that affected muscles will be susceptible to a re-loading injury when they begin return to earth or weight bearing. However, there is a paucity of literature evaluating the response of human unloaded muscle to exercise and return to activity. The purpose of this pilot study was to evaluate the soreness, function and strength response of muscle to re-loading in seven patients who were non-weight bearing for 6 weeks, compared to five healthy subjects. Function improved significantly over time for the patients but was still less than the healthy subjects over 12 weeks of physiotherapy. Concentric quadriceps muscle strength increased significantly over time for the patients. There was considerable variability in the patients' reports of muscle soreness but there were no significant changes over time or between groups.

MacIntyre, Donna L.; Eng, Janice J.; Allen, Trevor J.

2005-05-01

31

Quadriceps Fatigue Alters Human Muscle Performance during a Novel Weight Bearing Task  

PubMed Central

Limited information is currently available regarding muscle synergistic patterns and triggered reflex responses during dynamic weight bearing activities in the presence of muscle fatigue. Purpose The purpose of this study was to examine the effects of quadriceps muscle fatigue on patterns of muscle activation and performance in response to sudden, unexpected perturbations during a weight-bearing task. Methods Motion of the knee was measured as subjects were asked to track a visual target as accurately as possible while performing a resisted single leg squat task. Random perturbations were delivered in 20% of the trials by unexpectedly releasing the resistance during the flexion phase of the exercise. Absolute and constant errors were calculated to evaluate target tracking performance. Quadriceps and hamstring muscle activity was recorded during both perturbed and unperturbed trials. Twelve healthy females were tested before and after completing a repetitive submaximal eccentric quadriceps fatigue protocol. A second group of 12 females served as controls. Unexpected perturbations elicited long latency responses characterized by facilitation of the quadriceps and inhibition of the hamstrings. Results Muscle fatigue increased the amplitude of the long latency response in vastus lateralis by 4.3% maximum voluntary isometric contraction (p=.004). Changes in tracking error occurred in response to perturbations after fatigue in spite of significantly increased quadriceps muscle activity, especially during the extension phase of the exercise. Conclusion Quadriceps muscle fatigue alters the patterns of coordinated muscle activity and may render subjects less able to cope with unexpected perturbations during weight bearing tasks. PMID:20164810

Ballantyne, Bryon T.; Shields, Richard K.

2010-01-01

32

Evaluation of periprosthetic bone cysts in patients with a scandinavian total ankle replacement: weight-bearing conventional digital radiographs versus weight-bearing multiplanar reconstructed fluoroscopic imaging.  

PubMed

OBJECTIVE. Periprosthetic bone cysts are a known finding after total ankle replacement (TAR). The significance of cysts is uncertain, but they may threaten the long-term survival of the implant. The aim of this prospective study was to evaluate the diagnostic accuracy of weight-bearing digital radiography compared with 3D weight-bearing multiplanar reconstructed (MPR) fluoroscopic imaging when diagnosing periprosthetic bone cysts in patients who have undergone TAR. SUBJECTS AND METHODS. Forty-two consecutive patients with a Scandinavian Total Ankle Replacement (STAR) were consecutively enrolled and underwent digital radiography and 3D MPR imaging in the same session. All 3D MPR images were interpreted in a blinded fashion, specifically with regard to the presence and extent of periprosthetic bone cysts. Cysts were measured in three planes whenever possible. Interrater and intrarater reliability was assessed by using Cohen kappa test, and comparisons between the two modalities were performed with the Wilcoxon signed-rank and McNemar tests. RESULTS. Significantly more cysts were detected on 3D MPR (74 vs 55) (p = 0.03), with the mean size of cysts detected by 3D MPR significantly larger than that of cysts diagnosed on digital radiography (1545 mm(3) vs 253 mm(3)) (p < 0.0001). Statistical analysis based on the presence or absence of cysts in individual patients did not show a significant difference between 3D MPR and digital radiography (p = 0.23). CONCLUSION. The data imply that cysts are better detected and more accurately measured with 3D fluoroscopic MPR imaging compared with digital radiography, which underestimates not only the presence but also the extent of periprosthetic cysts. PMID:25247953

Jensen, Janni; Frøkjær, Johnny; Gerke, Oke; Ludvigsen, Lise; Torfing, Trine

2014-10-01

33

Initial non-weight-bearing therapy is important for preventing vertebral body collapse in elderly patients with clinical vertebral fractures  

PubMed Central

Purpose The aim of the present conventional observational study was to compare the clinical outcomes of initial non-weight-bearing therapy and conventional relative rest therapy among elderly patients with clinical vertebral fractures. Methods In total, 196 consecutive patients with clinical vertebral fractures (mean age: 78 years) who were hospitalized for treatment between January 1999 and March 2007 were analyzed. Initial non-weight-bearing therapy consisted of complete bed rest allowing rolling on the bed without any weight-bearing to the spine for 2 weeks, followed by rehabilitation wearing a soft brace. The indications for initial non-weight-bearing therapy were vertebral fracture involving the posterior portion of the vertebral body at the thoraco-lumbar spine, mild neurological deficit, instability of the fracture site, severe pain, multiple vertebral fractures arising from trauma, malalignment at the fracture site, and mild spinal canal stenosis caused by the fracture. Patients who met the indication criteria were treated with initial non-weight-bearing therapy (n = 103), while the other patients were treated with conventional relative rest (n = 93). All the patients were uniformly treated with intramuscular elcatonin to relieve pain. The primary endpoint was progression of the vertebral fracture. The secondary endpoints included bony union and subjective back pain. The follow-up period was 12 weeks. Results Compared with the conventional relative rest group, the collapse rate of the anterior and posterior portions of the vertebral body was significantly smaller in the initial non-weight-bearing group. The bony union rate was 100% in the initial non-weight-bearing group and 97% in the conventional relative rest group. The number of patients who experienced back pain was significantly lower in the initial non-weight-bearing group than in the conventional relative rest group. Conclusion These results suggest that initial non-weight-bearing therapy is important for preventing vertebral body collapse and for relieving pain among elderly patients with clinical vertebral fractures. PMID:22573944

Kishikawa, Yoichi

2012-01-01

34

Weight-Bearing Versus Nonweight-Bearing Exercise for Persons With Diabetes and Peripheral Neuropathy: A Randomized Controlled Trial  

PubMed Central

Objective To determine the effects of weight-bearing (WB) versus nonweight-bearing (NWB) exercise for persons with diabetes mellitus (DM) and peripheral neuropathy (PN). Design Randomized controlled trial with evaluations at baseline and after intervention. Setting University-based physical therapy research clinic. Participants Participants with DM and PN (N=29) (mean age ± SD, 64.5±12.5y; mean body mass index [kg/m2] ± SD, 35.5±7.3) were randomly assigned to WB (n=15) and NWB (n=14) exercise groups. All participants (100%) completed the intervention and follow-up evaluations. Interventions Group-specific progressive balance, flexibility, strengthening, and aerobic exercise conducted sitting or lying (NWB) or standing and walking (WB) occurred 3 times a week for 12 weeks. Main Outcome Measures Measures included the 6-minute walk distance (6MWD) and daily step counts. Secondary outcome measures represented domains across the International Classification of Functioning, Disability and Health. Results The WB group showed greater gains than the NWB group over time on the 6MWD and average daily step count (P<.05). The mean and 95% confidence intervals (CIs) between-group difference over time was 29m (95% CI, 6–51) for the 6MWD and 1178 (95% CI, 150–2205) steps for the average daily step count. The NWB group showed greater improvements than the WB group over time in hemoglobin A1c values (P<.05). Conclusions The results of this study indicate the ability of this population with chronic disease to increase 6MWD and daily step count with a WB exercise program compared with an NWB exercise program. PMID:23276801

Mueller, Michael J.; Tuttle, Lori J.; LeMaster, Joseph W.; Strube, Michael J; McGill, Janet B.; Hastings, Mary K.; Sinacore, David R.

2013-01-01

35

Weight-Bearing Exercise Accuracy Influences Muscle Activation Strategies of the Knee  

PubMed Central

Purpose Dynamic stability of the knee joint is a research topic of increasing focus after ACL injury, stroke, and incomplete spinal cord injury. Since rehabilitation programs use functional weight-bearing tasks to improve neuromuscular control of the knee, it is important to understand the adaptability of muscle control strategies during weight-bearing exercise. The purpose of this study was to compare muscle activation patterns during a single leg squat (SLS) exercise performed before and after feedback-controlled training. Methods This was a cross-sectional comparative study. Fifteen young, healthy individuals performed the SLS exercise while tracking a sinusoidal target with flexion and extension of the knee. The SLS instrument provided bidirectional resistance that was normalized to body weight. Six trials of 10 repetitions of the SLSs were performed to quantify improved performance (learning). Electromyographic activity from five muscles that cross the knee was analyzed. Accuracy of performance was measured by calculating the error between the target and actual knee displacement. Results Reduction in error measurements verified that individuals increased the accuracy of performance in each trial and retained this improvement across trials (p < 0.05). Modulation in muscle activity as a result of learning was reflected mainly in the biceps femoris, rectus femoris, and vastus lateralis muscles. Conclusion Increased accuracy with the SLS exercise was accompanied by a decrease in coactivation of selected musculature around the knee. This study presents a novel approach to quantify the effect of performance on muscle synergistic activation patterns during weight-bearing exercise. Controlled strengthening, as defined in this study, emphasizes accuracy of performance in conjunction with principles of strength training and has implications to knee control. PMID:17419885

Madhavan, Sangeetha; Shields, Richard K.

2014-01-01

36

Magnetic resonance imaging evaluation of weight-bearing subchondral trabecular bone in the knee  

Microsoft Academic Search

Objective  Changes in weight-bearing subchondral bone are central to osteoarthritis (OA) pathophysiology. Using MR, knee trabecular bone\\u000a is typically assessed in the axial plane, however partial volume artifacts limit the utility of MR methods for femorotibial\\u000a compartment subchondral bone analysis. Oblique-coronal acquisitions may enable direct visualization and quantification of\\u000a the expected increases in femorotibial subchondral trabecular bone.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  MR acquisition parameters were

Erika Schneider; Grace H. Lo; Gretchen Sloane; Lynn Fanella; David J. Hunter; Charles B. Eaton; Timothy E. McAlindon

2011-01-01

37

Alterations of collagen matrix in weight-bearing bones during skeletal unloading  

NASA Technical Reports Server (NTRS)

Skeletal unloading induces loss of bone mineral density in weight-bearing bones. The objectives of this study were to characterize the post-translational modifications of collagen of weight-bearing bones subjected to hindlimb unloading for 8 weeks. In unloaded bones, tibiae and femurs, while the overall amino acid composition was essentially identical in the unloaded and control tibiae and femurs, the collagen cross-link profile showed significant differences. Two major reducible cross-links (analyzed as dihydroxylysinonorleucine and hydroxylysinonorleucine) were increased in the unloaded bones. In addition, the ratios of the former to the latter as well as pyridinoline to deoxypyridinoline were significantly decreased in the unloaded bones indicating a difference in the extent of lysine hydroxylation at the cross-linking sites between these two groups. These results indicate that upon skeletal unloading the relative pool of newly synthesized collagen is increased and it is post-translationally altered. The alteration could be associated with impaired osteoblastic differentiation induced by skeletal unloading that results in a mineralization defect.

Shiiba, M.; Arnaud, S. B.; Tanzawa, H.; Uzawa, K.; Yamauchi, M.

2001-01-01

38

Outcomes of functional weight-bearing rehabilitation of Achilles tendon ruptures.  

PubMed

The introduction of functional rehabilitation for patients with Achilles tendon rupture has dramatically changed treatment programs for this condition. The authors introduced a functional weight-bearing protocol for patients with an acute Achilles tendon rupture treated operatively and nonoperatively in 2002. They hypothesized that no significant differences would exist in the rerupture rates and functional outcomes between the groups. Between 2002 and 2008, the authors collected data on 80 consecutive patients treated with a weight-bearing functional orthosis for complete Achilles tendon rupture. Following evidence-based counseling, 51 patients chose nonoperative treatment and 29 chose operative treatment. Outcome measures included rerupture rates, other complications, and functional scoring. The nonoperative group was a decade older (median age, 47 years [range, 27-80 years]) than the operative group (median age, 37 years [range, 24-55 years]). Rerupture was noted in 2 (4%) patients in the nonoperative treatment group and 1 (3%) patient in the operative group. Two (7%) patients in the operative group developed superficial wound infections and reported no nerve injuries. Median Achilles Tendon Total Rupture Score was 82 points in the nonoperative group and 94 in the operative group. Median Victorian Institute of Sports Assessment-Achilles tendinopathy questionnaire scores were 60 and 91 for the nonoperative and operative groups, respectively. Both groups had low rerupture rates. Functional scores, using the newly validated Achilles Tendon Total Rupture Score, were lower in the nonoperative group. PMID:23937753

Jackson, Gillian; Sinclair, Victoria F; McLaughlin, Charles; Barrie, James

2013-08-01

39

Ground reaction force and plantar pressure reduction in an incremental weight bearing system.  

PubMed

INTRODUCTION:: With increasing frequency, harness-supported treadmill ambulation has been advocated in patient use in order to provide reduction in weight-bearing to healing tissues and as a method which reduces the energy cost of treadmill ambulation. The purpose of this study was to analyse the ability of one of these devices (Zuni Exercise System) to support a percentage of a subject's body weight during walking and running and to explore the relationship of unloading to pressure reduction in selected plantar surface regions of the foot. METHODS:: Ten healthy male volunteers with no known foot pathology participated in this study. In-shoe plantar pressure (PEDAR) and vertical ground reaction force (GRF) were measured during walking and running at full body weight and at a 20% body[Figure: see text][Figure: see text] weight supported setting. Statistical evaluation used a one way ANOVA and a post-hoc paired t-test with significance set at p < 0.05. RESULTS:: Walking with a setting of 20% body weight supported was achieved with a reduction of the first and second vertical force peaks of 23.8+/-7.3% and 27.2+/-4.1% respectively, somewhat greater than the selected setting (Figure 1). The total force time integral during walking unloaded was 22.8+/-3.3%, which was only slightly greater than the selected 20% reduction. During running the active vertical force peak and total force time integral were reduced by 19.9+/-6.0% and 20.0+/-3.3% respectively during the unloaded condition (Figure 2). Plantar pressures were reduced from 6.8 - 27.8% during body weight supported conditions. The reduction in plantar pressure was variable across different regions of the foot with the toes in walking and the medial forefoot region in running being the least unloaded. DISCUSSION AND CONCLUSIONS:: The Zuni Exercise System appears to be a valid device to predictably reduce the vertical component of the GRF during walking and running with 20% body weight supported. Plantar pressures were reduced during body weight supported conditions but the reduction varied at different regions of the foot. However, the variability of the reduction across subjects was substantial, implying that a given regional pressure may not be as predictably reduced during a body weight supported condition. This highlights the difficulty a practitioner has in the ability to confidently reduce pressure by a set amount in a selected foot region by using assistive devices without direct in-shoe measurements. PMID:11415712

Flynn, TW; Canavan, PK; Chiang, JH; Cavanagh, PR

1997-04-01

40

Early weight-bearing after periacetabular osteotomy leads to a high incidence of postoperative pelvic fractures  

PubMed Central

Background It has not been shown whether accelerated rehabilitation following periacetabular osteotomy (PAO) is effective for early recovery. The purpose of this retrospective study was to compare complication rates in patients with standard and accelerated rehabilitation protocols who underwent PAO. Methods Between January 2002 and August 2011, patients with a lateral center-edge (CE) angle of?weight-bearing with two crutches started 2 months postoperatively in 73 patients (80 hips) with the standard rehabilitation protocol. In 65 patients (76 hips) with the accelerated rehabilitation protocol, postoperative strengthening of the hip, thigh and core musculature was begun on the day of surgery as tolerated. The exercise program included active hip range of motion, and gentle isometric hamstring and quadriceps muscle sets; these exercises were performed for 30 minutes in the morning and 30 minutes in the afternoon with a physical therapist every weekday for 6 weeks. Full weight-bearing with two axillary crutches started on the day of surgery as tolerated. Complications were evaluated for 2 years. Results The clinical results at the time of follow-up were similar in the two groups. The average periods between the osteotomy and full-weight-bearing walking without support were 4.2 months and 6.9 months in patients with the accelerated and standard rehabilitation protocols (P?

2014-01-01

41

Acetabular roof arc angles and anatomic biomechanical superior acetabular weight bearing area  

PubMed Central

Background: Acetabular fracture involves whether superior articular weight bearing area and stability of the hip are assessed by acetabular roof arc angles comprising medial, anterior and posterior. Many previous studies, based on clinical, biomechanics and anatomic superior articular surface of acetabulum showed different degrees of the angles. Anatomic biomechanical superior acetabular weight bearing area (ABSAWBA) of the femoral head can be identified as radiographic subchondral bone density at superior acetabular dome. The fracture passes through ABSAWBA creating traumatic hip arthritis. Therefore, acetabular roof arc angles of ABSAWBA were studied in order to find out that the most appropriate degrees of recommended acetabular roof arc angles in the previous studies had no ABSAWBA involvement. Materials and Methods: ABSAWBA of femoral head was identified 68 acetabular fractures and 13 isolated pelvic fractures without unstable pelvic ring injury were enrolled. Acetabular roof arc angle was measured on anteroposterior, obturator and iliac oblique view radiographs of normal contralateral acetabulum using programmatic automation controller digital system and measurement tools. Results: Average medial, anterior and posterior acetabular roof arc angles of the ABSAWBA of 94 normal acetabulum were 39.09 (7.41), 42.49 (8.15) and 55.26 (10.08) degrees, respectively. Conclusions: Less than 39°, 42° and 55° of medial, anterior and posterior acetabular roof arc angles involve ABSAWBA of the femoral head. Application of the study results showed that 45°, 45° and 62° from the previous studies are the most appropriate medial, anterior and posterior acetabular roof arc angles without involvement of the ABSAWBA respectively.

Harnroongroj, Thossart; Wattanakaewsripetch, Montri; Sudjai, Narumol; Harnroongroj, Thos

2014-01-01

42

Prediction of Food Intakes, Weight Gains, Organ Weights, and Tumor Size in Tumor-bearing Rats by the Four-Parameter Mathematical Model for Physiological Responses1  

Microsoft Academic Search

Groups of male weanling rats bearing the transplantable Novikoff ascites hepatoma were fed diets containing graded levels of protein. The food intakes and weight gains were recorded daily. Seven days after inoculation of the rats with the tumor (6 days in Experiment 2), the rats were sacrificed, their organs were weighed, and the tumor and ascites fluid volumes were determined.

William T. Briscoe; L. Preston Mercer; Dixie Gimlin; Jim Ramlet

43

Balance Asymmetry in Parkinson's Disease and Its Contribution to Freezing of Gait  

PubMed Central

Balance control (the ability to maintain an upright posture) is asymmetrically controlled in a proportion of patients with Parkinson’s disease. Gait asymmetries have been linked to the pathophysiology of freezing of gait. We speculate that asymmetries in balance could contribute to freezing by a) hampering the unloading of the stepping leg and/or b) leading to a preferred stance leg during gait, which then results in asymmetric gait. To investigate this, we examined the relationship between balance control and weight-bearing asymmetries and freezing. We included 20 human patients with Parkinson (tested OFF medication; nine freezers) and nine healthy controls. Balance was perturbed in the sagittal plane, using continuous multi-sine perturbations, applied by a motion platform and by a force at the sacrum. Applying closed-loop system identification techniques, relating the body sway angle to the joint torques of each leg separately, determined the relative contribution of each ankle and hip joint to the total amount of joint torque. We also calculated weight-bearing asymmetries. We determined the 99-percent confidence interval of weight-bearing and balance-control asymmetry using the responses of the healthy controls. Freezers did not have larger asymmetries in weight bearing (p?=?0.85) nor more asymmetrical balance control compared to non-freezers (p?=?0.25). The healthy linear one-to-one relationship between weight bearing and balance control was significantly different for freezers and non-freezers (p?=?0.01). Specifically, non-freezers had a significant relationship between weight bearing and balance control (p?=?0.02), whereas this relation was not significant for freezers (p?=?0.15). Balance control is asymmetrical in most patients (about 75 percent) with Parkinson’s disease, but this asymmetry is not related to freezing. The relationship between weight bearing and balance control seems to be less pronounced in freezers, compared to healthy controls and non-freezers. However, this relationship should be investigated further in larger groups of patients. PMID:25032994

Boonstra, Tjitske A.; van Vugt, Jeroen P. P.; van der Kooij, Herman; Bloem, Bastiaan R.

2014-01-01

44

Side-to-side weight-bearing asymmetry in subjects with low back pain.  

PubMed

The purpose of this project was to determine if subjects with low back pain (LBP) exhibit greater side-to-side weight-bearing (WB) asymmetry compared to healthy control subjects without LBP. This study utilized an observational double cohort design and consisted of 35 subjects with LBP and 31 healthy control subjects. Side-to-side WB asymmetry was calculated as the average of the absolute value of the difference between the right and left lower extremity from three trials. The percentage of the average side-to-side WB asymmetry relative to the total body weight was calculated to normalize expected differences in magnitude of asymmetry based on a subject's total body weight. An 11-point numeric pain rating scale was used to represent the subject's current level of pain. Patients with LBP demonstrated significantly greater normalized side-to-side WB asymmetry than healthy control subjects (8.8% vs. 3.6%, respectively, P<0.001). In patients with LBP, higher magnitudes of side-to-side WB asymmetry were significantly associated with increased pain (r=0.39, P=0.021). In conclusion patients with LBP exhibited increased side-to-side WB asymmetry compared to healthy control subjects without LBP. This asymmetry was associated with increased levels of pain. This finding is relevant for planning future studies that will attempt to provide evidence for the construct validity of manipulation by determining if side-to-side WB asymmetry normalizes after a manipulation intervention and if this improvement is associated with improvements in pain and function. PMID:12909437

Childs, J D; Piva, S R; Erhard, R E; Hicks, G

2003-08-01

45

Non-weight bearing-induced muscle weakness: the role of myosin quantity and quality in MHC type II fibers  

PubMed Central

We tested the hypothesis that non-weight bearing-induced muscle weakness (i.e., specific force) results from decreases in myosin protein quantity (i.e., myosin content per half-sarcomere and the ratio of myosin to actin) and quality (i.e., force per half-sarcomere and population of myosin heads in the strong-binding state during muscle contraction) in single myosin heavy chain (MHC) type II fibers. Fisher-344 rats were assigned to weight-bearing control (Con) or non-weight bearing (NWB). The NWB rats were hindlimb unloaded for 2 wk. Diameter, force, and MHC content were determined in permeabilized single fibers from the semimembranosus muscle. MHC isoform and the ratio of MHC to actin in each fiber were determined by gel electrophoresis and silver staining techniques. The structural distribution of myosin from spin-labeled fiber bundles during maximal isometric contraction was evaluated using electron paramagnetic resonance spectroscopy. Specific force (peak force per cross-sectional area) in MHC type IIB and IIXB fibers from NWB was significantly reduced by 38% and 18%, respectively. MHC content per half-sarcomere was significantly reduced by 21%. Two weeks of hindlimb unloading resulted in a reduced force per half-sarcomere of 52% and fraction of myosin strong-binding during contraction of 34%. The results suggest that reduced myosin and actin content (quantity) and myosin quality concomitantly contribute to non-weight bearing-related muscle weakness. PMID:24829495

Kim, Jong-Hee

2014-01-01

46

Comparison of dermatoscopic images of acral lentiginous melanoma and acral melanocytic nevus occurring on body weight-bearing areas  

PubMed Central

Background: Because body weight-bearing produces a shift in the horny layer, acral melanocytic nevus on the body weight-bearing area of the sole showed a regular fibrillar pattern (FP) due to slanting of the melanin columns in the horny layer. On the other hand, acral lentiginous melanoma (ALM) on the body weight-bearing area of the sole tended to show irregular fibrillar pattern showing rather structureless pigmentation instead of a parallel ridge pattern, which is due to the shift of the horny layer. Objective: To elucidate the subtle difference between the regular FP of nevus and irregular FP in ALM. Methods: In this study, the dermatoscopic features of five cases of ALM and five cases of acral melanocytic nevus on the weight-bearing area of the sole were compared. Results: All the cases with nevi showed regular FP showing regular distribution of fibrils, whereas all the melanomas showed irregular distribution of fibrils and colors. Fibrils in nevi tended to be clear at the furrows and dim at the ridges. White fibrils corresponding to the eccrine ducts in the horny layer were more often present on the ridges in ALM, which showed negative FP. Conclusion: Differentiating between the regular and irregular FP, including negative FP, might be helpful for the discrimination of melanoma from nevus. PMID:25396085

Watanabe, Soko; Sawada, Mizuki; Ishizaki, Sumiko; Kobayashi, Ken; Tanaka, Masaru

2014-01-01

47

Non-weight bearing-induced muscle weakness: the role of myosin quantity and quality in MHC type II fibers.  

PubMed

We tested the hypothesis that non-weight bearing-induced muscle weakness (i.e., specific force) results from decreases in myosin protein quantity (i.e., myosin content per half-sarcomere and the ratio of myosin to actin) and quality (i.e., force per half-sarcomere and population of myosin heads in the strong-binding state during muscle contraction) in single myosin heavy chain (MHC) type II fibers. Fisher-344 rats were assigned to weight-bearing control (Con) or non-weight bearing (NWB). The NWB rats were hindlimb unloaded for 2 wk. Diameter, force, and MHC content were determined in permeabilized single fibers from the semimembranosus muscle. MHC isoform and the ratio of MHC to actin in each fiber were determined by gel electrophoresis and silver staining techniques. The structural distribution of myosin from spin-labeled fiber bundles during maximal isometric contraction was evaluated using electron paramagnetic resonance spectroscopy. Specific force (peak force per cross-sectional area) in MHC type IIB and IIXB fibers from NWB was significantly reduced by 38% and 18%, respectively. MHC content per half-sarcomere was significantly reduced by 21%. Two weeks of hindlimb unloading resulted in a reduced force per half-sarcomere of 52% and fraction of myosin strong-binding during contraction of 34%. The results suggest that reduced myosin and actin content (quantity) and myosin quality concomitantly contribute to non-weight bearing-related muscle weakness. PMID:24829495

Kim, Jong-Hee; Thompson, LaDora V

2014-07-15

48

Coordination strategies for limb forces during weight-bearing locomotion in normal rats, and in rats spinalized as neonates  

PubMed Central

Some rats spinally transected as neonates (ST rats) achieve weight-supporting independent locomotion. The mechanisms of coordinated hindlimb weight support in such rats are not well understood. To examine these in such ST rats and normal rats, rats with better than 60% of weight supported steps on a treadmill as adults were trained to cross an instrumented runway. Ground reaction forces, coordination of hindlimb and forelimb forces and the motions of the center of pressure were assessed. Normal rats crossed the runway with a diagonal trot. On average hindlimbs bore about 80% of the vertical load carried by forelimbs, although this varied. Forelimbs and hindlimb acted synergistically to generate decelerative and propulsive rostrocaudal forces, which averaged 15% of body weight with maximums of 50% . Lateral forces were very small (<8% of body weight). Center of pressure progressed in jumps along a straight line with mean lateral deviations <1 cm. ST rats hindlimbs bore about 60% of the vertical load of forelimbs, significantly less compared to intact (p<0.05). ST rats showed similar mean rostrocaudal forces, but with significantly larger maximum fluctuations of up to 80% of body weight (p<0.05). Joint force-plate recordings showed forelimbs and hindlimb rostrocaudal forces in ST rats were opposing and significantly different from intact rats (p<0.05). Lateral forces were ~20% of body weight and significantly larger than in normal rats (p<0.05). Center of pressure zig-zagged, with mean lateral deviations of ~ 2cm and a significantly larger range (p<0.05). The haunches were also observed to roll more than normal rats. The locomotor strategy of injured rats using limbs in opposition was presumably less efficient but their complex gait was statically stable. Because forelimbs and hindlimbs acted in opposition, the trunk was held compressed. Force coordination was likely managed largely by the voluntary control in forelimbs and trunk. PMID:18612631

Giszter, Simon F; Davies, Michelle R; Graziani, Virginia

2010-01-01

49

A new method to assess weight-bearing distribution after central nervous system lesions in rats.  

PubMed

The aim of the present study is to assess the relevance of weight-bearing distribution (DWB) measurement in freely moving rats after stroke and thoracic spinal cord injuries. Animals were divided in 2 experiments: (1) The middle cerebral artery occlusion-reperfusion (MCAO-r) experiment containing the MCAO group in which focal brain ischaemia was induced by transient MCA occlusion and (2) the thoracic hemisection experiment containing the TH group in which a spinal cord hemisection was performed at the T10 level. A Control and respective Sham groups were also included in each experiment. Not only the pressure exerted by each paw was measured but also different ratios such as: (1) the sum of the right and the left forepaws was normalized by the sum of the right and the left hindpaws (F/H), (2) the left forepaw was normalized by the right forepaw (LF/RF), (3) the left hindpaw was normalized by the right hindpaw (LH/RH). Additionally, the times spent on 3 paws and on 4 paws were measured. Only the time spent on 4 paws was shorter in the MCAO group than in the Control (p<0.001) and in the Sham (p<0.01) groups. The LH/RH ratio of the TH group at the 1st week was lower (p<0.01) than the pre-surgical value. Moreover, its F/H ratio was superior (p<0.001) to the ones of the Control and the Sham groups. Our study indicates that DWB should be more frequently used to evaluate both the severity of central nervous system traumas and the effectiveness of pharmacological and/or rehabilitation strategies. PMID:24200548

Pertici, Vincent; Pin-Barre, Caroline; Felix, Marie-Solenne; Laurin, Jérôme; Brisswalter, Jeanick; Decherchi, Patrick

2014-02-01

50

Weight-bearing exercise and bone mineral accrual in children and adolescents: A review of controlled trials  

Microsoft Academic Search

IntroductionOsteoporosis is a serious skeletal disease and as there is currently no cure, there is a large emphasis on its prevention, including the optimisation of peak bone mass. There is increasing evidence that regular weight-bearing exercise is an effective strategy for enhancing bone status during growth. This systematic review evaluates randomised and non-randomised controlled trials to date, on the effects

K. Hind; M. Burrows

2007-01-01

51

Synergistic ablation does not affect atrophy or altered myosin heavy chain expression in the non-weight bearing soleus muscle  

NASA Technical Reports Server (NTRS)

The purpose of this study was to investigate whether the soleus muscle undergoes atrophy and alterations in myosin heavy chain (MHC) composition during non-weight bearing in the absence of synergists. Thirty-two female rats were randomly assigned to four groups: control (C), synergistic ablation (ABL) of the gastrocnemius and plantaris muscles to overload the soleus muscle, hindlimb suspension (HLS), or a combination of synergistic ablation and hindlimb suspension (HLS-ABL). After 28 days of hindlimb suspension, soleus atrophy was more pronounced in HLS (58%) than in HLS-ABL (43%) rats. Compared to C rats, non-weight bearing decreased mixed and myofibrillar protein contents and Type I MHC 49%, 45%, and 7%, respectively, in HLS animals. In addition, de novo expression of fast Type IIx and Type IIb MHC (5% and 2%, respectively) was observed in HLS animals. Similarly, when compared to C rats, mixed and myofibrillar protein contents and Type I MHC decreased 43%, 46%, and 4%, respectively, in HLS-ABL animals. Also, de novo expression of Type IIx (4%) and IIb (1%) MHC was observed. Collectively, these data indicate that the loss of muscle protein and Type I MHC, and the de novo expression of Type IIx and Type IIb MHC in the rat soleus occur independently of the presence of synergists during non-weight bearing. Furthermore, these results confirm the contention that soleus mass and MHC expression are highly sensitive to alterations in mechanical load.

Linderman, J. K.; Talmadge, R. J.; Gosselink, K. L.; Tri, P. N.; Roy, R. R.; Grindeland, R. E.

1996-01-01

52

Study of the polycarbonate-urethane/metal contact in different positions during gait cycle.  

PubMed

Nowadays, a growing number of young and more active patients receive hip replacement. More strenuous activities in such patients involve higher friction and wear rates, with friction on the bearing surface being crucial to ensure arthroplasty survival in the long term. Over the last years, the polycarbonate-urethane has offered a feasible alternative to conventional bearings. A finite element model of a healthy hip joint was developed and adjusted to three gait phases (heel strike, mid-stance, and toe-off), serving as a benchmark for the assessment of the results of joint replacement model. Three equivalent models were made with the polycarbonate-urethane Tribofit system implanted, one for each of the three gait phases, after reproducing a virtual surgery over the respective healthy models. Standard body-weight loads were considered: 230% body-weight toe-off, 275% body-weight mid-stance, and 350% body-weight heel strike. Contact pressures were obtained for the different models. When comparing the results corresponding to the healthy model to polycarbonate-urethane joint, contact areas are similar and so contact pressures are within a narrower value range. In conclusion, polycarbonate-urethane characteristics are similar to those of the joint cartilage. So, it is a favorable alternative to traditional bearing surfaces in total hip arthroplasty, especially in young patients. PMID:25247180

Gabarre, Sergio; Herrera, Antonio; Mateo, Jesús; Ibarz, Elena; Lobo-Escolar, Antonio; Gracia, Luis

2014-01-01

53

Study of the Polycarbonate-Urethane/Metal Contact in Different Positions during Gait Cycle  

PubMed Central

Nowadays, a growing number of young and more active patients receive hip replacement. More strenuous activities in such patients involve higher friction and wear rates, with friction on the bearing surface being crucial to ensure arthroplasty survival in the long term. Over the last years, the polycarbonate-urethane has offered a feasible alternative to conventional bearings. A finite element model of a healthy hip joint was developed and adjusted to three gait phases (heel strike, mid-stance, and toe-off), serving as a benchmark for the assessment of the results of joint replacement model. Three equivalent models were made with the polycarbonate-urethane Tribofit system implanted, one for each of the three gait phases, after reproducing a virtual surgery over the respective healthy models. Standard body-weight loads were considered: 230% body-weight toe-off, 275% body-weight mid-stance, and 350% body-weight heel strike. Contact pressures were obtained for the different models. When comparing the results corresponding to the healthy model to polycarbonate-urethane joint, contact areas are similar and so contact pressures are within a narrower value range. In conclusion, polycarbonate-urethane characteristics are similar to those of the joint cartilage. So, it is a favorable alternative to traditional bearing surfaces in total hip arthroplasty, especially in young patients. PMID:25247180

Herrera, Antonio; Mateo, Jesus; Lobo-Escolar, Antonio

2014-01-01

54

Biofeedback rehabilitation of posture and weight-bearing distribution in stroke: a center of foot pressure analysis  

PubMed Central

Summary Weight bearing on the paretic lower extremity and transfer of weight from one lower extremity to the other are important goals of stroke rehabilitation. Improvements in these limb loading and weight transfer abilities have been shown to relate to improved performance of many functional activities. Unfortunately, valid and practical clinical measures of paretic lower extremity loading and weight transfer have not been identified. The purpose of this study was to quantitatively assess, through center of foot pressure (CoP) analysis of quiet upright stance control, recovery of paretic limb loading as a measure of weight transfer in early stroke subjects, testing the effectiveness of a targeted rehabilitation intervention based on audio-visual biofeedback. Thirty-seven adults with lower extremity motor impairment following unilateral, non-cerebellar stroke, were tested twice, at an interval of at least one month post stroke and following rehabilitation intervention aimed at correcting their asymmetrical weight bearing. The intervention was performed with (Study Group, SG) or without (Control Group, CG) a postural audio-visual biofeedback approach. Indices of postural stability and of balance control asymmetry were estimated by acquiring the movements of the CoP during quiet upright stance condition with or without visual input (eyes open, EO and eyes closed, EC). Clinical scales were also administered. Both the CG and the SG subjects showed improved control in upright stance posture as documented by significant improvements in the scale scores and indices of stability during both the EO and the EC condition. Only the SG showed a significantly reduced CoP index of asymmetry. The CoP index of asymmetry, correlating with clinical motor scales, is a valid measure of paretic limb loading during stroke recovery. Postural audio-visual biofeedback represented the more effective approach for reducing weight loading asymmetry of the lower limbs in stroke. PMID:25306123

De Nunzio, Alessandro Marco; Zucchella, Chiara; Spicciato, Francesca; Tortola, Paolo; Vecchione, Carmine; Pierelli, Francesco; Bartolo, Michelangelo

2014-01-01

55

Gait Analysis for Classification  

E-print Network

This thesis describes a representation of gait appearance for the purpose of person identification and classification. This gait representation is based on simple localized image features such as moments extracted from ...

Lee, Lily

2003-06-26

56

Gait analysis for classification  

E-print Network

This thesis describes a representation of gait appearance for the purpose of person identification and classification. This gait representation is based on simple localized image features such as moments extracted from ...

Lee, Lily, 1971-

2002-01-01

57

Gait Characteristic Analysis and Identification Based on the iPhone's Accelerometer and Gyrometer  

PubMed Central

Gait identification is a valuable approach to identify humans at a distance. In this paper, gait characteristics are analyzed based on an iPhone's accelerometer and gyrometer, and a new approach is proposed for gait identification. Specifically, gait datasets are collected by the triaxial accelerometer and gyrometer embedded in an iPhone. Then, the datasets are processed to extract gait characteristic parameters which include gait frequency, symmetry coefficient, dynamic range and similarity coefficient of characteristic curves. Finally, a weighted voting scheme dependent upon the gait characteristic parameters is proposed for gait identification. Four experiments are implemented to validate the proposed scheme. The attitude and acceleration solutions are verified by simulation. Then the gait characteristics are analyzed by comparing two sets of actual data, and the performance of the weighted voting identification scheme is verified by 40 datasets of 10 subjects. PMID:25222034

Sun, Bing; Wang, Yang; Banda, Jacob

2014-01-01

58

Interactive gait training device \\  

Microsoft Academic Search

In this paper, we evaluated the effectiveness of Walk-Mate, which has been used mainly as a gait compensation device, as a gait rehabilitation training device by analyzing improvement in locomotion before, during and after rehabilitation in hemiparetic patients and comparing it with a previous gait training method. Walk-Mate generates a model walking rhythm in response to a user's locomotion in

Barbara Herzberger; Joachim Hermsdorfer; Yoshihiro Miyake; Ernst Poppel

2007-01-01

59

Muscle glucose uptake in the rat after suspension with single hindlimb weight bearing  

NASA Technical Reports Server (NTRS)

An examination is conducted of the effect of nonweight-bearing conditions, and the systemic influences of simulated microgravity on rat hindlimb muscles. The results obtained suggest that the increases in hindlimb muscle glucose uptake and extracellular space associated with simulated microgravity persist with hindlimb weightbearing, despite the prevention of muscle atrophy. The mechanism (or mechanisms) responsible for these effects are currently unknown.

Stump, Craig S.; Woodman, Christopher R.; Fregosi, Ralph F.; Tipton, Charles M.

1993-01-01

60

Bone loss during partial weight bearing (1/6th gravity) is mitigated by resistance and aerobic exercise in mice  

NASA Astrophysics Data System (ADS)

Astronauts on long duration missions continue to experience bone loss, as much as 1-2% each month, for up to 4.5 years after a mission. Mechanical loading of bone with exercise has been shown to increase bone formation, mass, and geometry. The aim of this study was to compare the efficacy of two exercise protocols during a period of reduced gravitational loading (1/6th body weight) in mice. Since muscle contractions via resistance exercise impart the largest physiological loads on the skeleton, we hypothesized that resistance training (via vertical tower climbing) would better protect against the deleterious musculoskeletal effects of reduced gravitational weight bearing when compared to endurance exercise (treadmill running). Young adult female BALB/cBYJ mice were randomly assigned to three groups: 1/6 g (G/6; n=6), 1/6 g with treadmill running (G/6+RUN; n=8), or 1/6 g with vertical tower climbing (G/6+CLB; n=9). Exercise was performed five times per week. Reduced weight bearing for 21 days was achieved through a novel harness suspension system. Treadmill velocity (12-20 m/min) and daily run time duration (32-51 min) increased incrementally throughout the study. Bone geometry and volumetric bone mineral density (vBMD) at proximal metaphysis and mid-diaphysis tibia were assessed by in vivo peripheral quantitative computed tomography (pQCT) on days 0 and 21 and standard dynamic histomorphometry was performed on undemineralized sections of the mid-diaphysis after tissue harvest. G/6 caused a significant decrease (P<0.001) in proximal tibia metaphysis total vBMD (-9.6%). These reductions of tibia metaphyseal vBMD in G/6 mice were mitigated in both G/6+RUN and G/6+CLB groups (P<0.05). After 21 days of G/6, we saw an absolute increase in tibia mid-diaphysis vBMD and in distal metaphysis femur vBMD in both G/6+RUN and G/6+CLB mice (P<0.05). Substantial increases in endocortical and periosteal mineralizing surface (MS/BS) at mid-diaphysis tibia in G/6+CLB demonstrate that bone formation can be increased even in the presence of reduced weight bearing. These data suggest that moderately vigorous endurance exercise and resistance training, through treadmill running or climb training mitigates decrements in vBMD during 21 days of reduced weight bearing. Consistent with our hypothesis, tower climb training, most pronounced in the tibia mid-diaphysis, provides a more potent osteogenic response compared to treadmill running.

Boudreaux, R. D.; Metzger, C. E.; Macias, B. R.; Shirazi-Fard, Y.; Hogan, H. A.; Bloomfield, S. A.

2014-06-01

61

Slow gait in MCI is associated with ventricular enlargement: results from the Gait and Brain Study.  

PubMed

Slow gait is ubiquitous among older adults and predicts cognitive decline and progression to dementia. Age-related structural brain changes could be responsible for abnormal gait. The purpose of this study was to determine whether brain lateral ventricle volume, a measure of brain atrophy, was associated with gait velocity among older adults with mild cognitive impairment (MCI), while considering the effects of age and brain vascular burden. Twenty community-dwellers with MCI, free of hydrocephalus, aged 76 years (69/80) [median (25th/75th percentile)] (35 % female) from the 'Gait and Brain Study' were included in this analysis. Quantitative gait performance was measured while steady-state walking at self-selected pace with a 6-m electronic portable walkway (GAITRite). Brain ventricle volume was quantified using semi-automated software from three-dimensional T1-weighted magnetic resonance imaging. Age, white matter hyperintensity burden and Mini-Mental State Examination score were used as potential confounders. Median gait velocity was 118.7 cm/s (104.4/131.3). Median brain ventricle volume was 39.9 mL (30.0/46.6) with the left ventricle being slightly larger than the right (P = 0.052). Brain ventricle volume was inversely associated with gait velocity (adjusted ? = -0.63, P = 0.046). Volume of both the ventricular main bodies and the temporal horns correlated inversely with gait velocity (respectively, P = 0.009, P = 0.008). Left ventricle volume correlated with decreased gait velocity (P = 0.002) while right ventricle did not (P = 0.068). Slower gait velocity was associated with larger brain ventricle volume in our sample of people with MCI independent of age, cerebrovascular burden and cognitive worsening. This result may help elucidate the trajectories of cognitive and gait declines in people with MCI. PMID:23196981

Annweiler, C; Beauchet, O; Bartha, R; Montero-Odasso, M

2013-07-01

62

A mechanized gait trainer for restoring gait in nonambulatory subjects  

Microsoft Academic Search

Hesse S, Uhlenbrock D, Werner C, Bardeleben A. A mechanized gait trainer for restoring gait in nonambulatory subjects. Arch Phys Med Rehabil 2000;81:1158-61. Objective: To construct an advanced mechanized gait trainer to enable patients the repetitive practice of a gaitlike movement without overstraining therapists. Device: Prototype gait trainer that simulates the phases of gait (by generating a ratio of 40%

Stefan Hesse; Dietmar Uhlenbrock; Cordula Werner; Anita Bardeleben

2000-01-01

63

Do external stimuli impact the gait of children with idiopathic toe walking? A study protocol for a within-subject randomised control trial  

PubMed Central

Introduction Frequently, toe walking gait is the result of disease processes, trauma or neurogenic influences. Idiopathic toe walking (ITW) is, by definition, the diagnosis of a toe walking gait adopted in the absence of one of these medical conditions. Long-term ITW has been associated with reduced ankle range of motion. Reported treatments have included serial casting, Botulinum toxin type A or surgery to improve the ankle range of motion. Investigating the impact of simple and non-invasive treatment options for ITW is important for future research and clinical outcomes. This study investigates the immediate impact of footwear, footwear with orthotics and whole body vibration on ITW to determine if any one intervention improves heel contact and spatial-temporal gait measures. This determination is important for future clinical trials into treatment effectiveness. Methods and analysis Design: this protocol describes a within-subject randomised controlled trial that measures changes in gait following changes in external stimuli. Participants: 15 children diagnosed with an ITW gait will be recruited from the Victorian Paediatric Rehabilitation Service at Monash Children's Hospital Toe Walking Clinic provided they have ITW and meet the inclusion criteria. Procedure: participants will have their gait recorded walking barefoot, in usual footwear, a custom-made, full-length carbon fibre orthotic in usual footwear and following whole body vibration. Outcome measures will include the presence of bilateral heel contact preintervention and postintervention, stride length (cm), stride width (cm), left and right stride time (s), left and right stance and swing percentage of the gait cycle, gait velocity (m/s), left and right foot toe in/toe out angle (°) and weight-bearing lunge pre and post each condition. Ethics and dissemination The results of this study will be published at the conclusion and have been approved by Southern Health HREC:12102B. Clinical trial registry number ACTRN12612000975897. PMID:23454667

Williams, Cylie M; Michalitsis, Joanne; Murphy, Anna; Rawicki, Barry; Haines, Terry P

2013-01-01

64

Gait analysis of walking before and after medial opening wedge high tibial osteotomy  

Microsoft Academic Search

Introduction  Medial opening wedge high tibial osteotomy (HTO) is used to treat medial compartment osteoarthritis (OA) of the knee. HTO\\u000a shifts the weight-bearing line from the medial compartment into the lateral compartment. The aim of this study was to investigate\\u000a the functional biomechanical consequences of this alteration in alignment.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Eleven male patients with medial compartment osteoarthritis underwent three-dimensional gait analysis during

Martin Lind; Jodie McClelland; Joanne E. Wittwer; Timothy S. Whitehead; Julian A. Feller; Kate E. Webster

65

Carried Load Measurement Based on Gait Analysis and Human Kinetics  

Microsoft Academic Search

As a means of biometric identification, gait analysis has attracted much attention in both research and industry. Most methods focus on human posture identification, tracking and medicine treatment assistant. Few methods, however, investigate the relationship between the load carried by an individual and the characteristics of his\\/her gait. In this paper, we present a method to estimate the weight of

Kui Zhang; Hong Zhang; Ning Yao; Robert J. Sclabassi; Mingui Sun

2008-01-01

66

Gait characteristic analysis and identification based on the iPhone's accelerometer and gyrometer.  

PubMed

Gait identification is a valuable approach to identify humans at a distance. In this paper, gait characteristics are analyzed based on an iPhone's accelerometer and gyrometer,and a new approach is proposed for gait identification. Specifically, gait datasets are collected by the triaxial accelerometer and gyrometer embedded in an iPhone. Then, the datasets are processed to extract gait characteristic parameters which include gait frequency, symmetry coefficient, dynamic range and similarity coefficient of characteristic curves. Finally, a weighted voting scheme dependent upon the gait characteristic parameters is proposed forgait identification. Four experiments are implemented to validate the proposed scheme. The attitude and acceleration solutions are verified by simulation. Then the gait characteristics are analyzed by comparing two sets of actual data, and the performance of the weighted voting identification scheme is verified by 40 datasets of 10 subjects. PMID:25222034

Sun, Bing; Wang, Yang; Banda, Jacob

2014-01-01

67

Orientation of the first metatarsal base wedge osteotomy: perpendicular to the metatarsal versus weight-bearing surface.  

PubMed

Changes have been proposed in the orientation of the first metatarsal base closing abductory wedge osteotomy based on sound theoretical reasoning. The newer proposed method, utilizing an orientation of the osteotomy perpendicular to the weight-bearing surface, produces only pure transverse plane motion and no loss of ground contact by hinge axis mechanisms. In contrast, the traditional orientation of the osteotomy, perpendicular to the long axis of the metatarsal, produces extraneous frontal plane motion that results in loss of ground contact as the osteotomy site is closed. The presented study formulates a mathematical model to calculate the amount of loss of ground contact produced by the traditional osteotomy orientation. The values obtained from 168 calculations suggest far less clinical significance to the change than has been implied or stated previously. PMID:3225387

Palladino, S J

1988-01-01

68

The Pathomechanics Of Calcaneal Gait  

NASA Astrophysics Data System (ADS)

The data acquisition system employed in our laboratory includes optical, electronic and computer subsystems. Three movie camera freeze the motion for analysis. The film is displayed on a motion analyzer, and the body segment positions are recorded in a three dimensional coordinate system with Graf/pen sonic digitizer. The angular rotations are calculated by computer and automatically plotted. The force plate provides measurements of vertical force, foreaft shear, medial-lateral shear, torque, and center of pressure. Electromyograms are superimposed upon gait movies to permit measurement of muscle phasic activity. The Hycam movie camera si-multaneously films (through separate lens) the subject and oscilloscope. Movement measurements, electromyograms, and floor reaction forces provide the data base for analysis. From a study of the gait changes in five normal subjects following tibial nerve block, and from additional studies of patients with paralysis of the ankle plantar flexors, the pathomechanics of calcaneal gait can be described. Inability to transfer weight to the forward part of the foot produces ankle instability and reduction of contralateral step length. Excessive drop of the center of mass necessitates com-pensatory increased lift energy output through the sound limb to restore the height of the center of mass. Excessive stance phase ankle dorsiflexion produces knee instability requiring prolonged quadriceps muscle phasic activity.

Sutherland, David H.; Cooper, Les

1980-07-01

69

Recognition using gait.  

SciTech Connect

Gait or an individual's manner of walking, is one approach for recognizing people at a distance. Studies in psychophysics and medicine indicate that humans can recognize people by their gait and have found twenty-four different components to gait that taken together make it a unique signature. Besides not requiring close sensor contact, gait also does not necessarily require a cooperative subject. Using video data of people walking in different scenarios and environmental conditions we develop and test an algorithm that uses shape and motion to identify people from their gait. The algorithm uses dynamic time warping to match stored templates against an unknown sequence of silhouettes extracted from a person walking. While results under similar constraints and conditions are very good, the algorithm quickly degrades with varying conditions such as surface and clothing.

Koch, Mark William

2007-09-01

70

Evaluation of a bisphosphonate enriched ultra-high molecular weight polyethylene for enhanced total joint replacement bearing surface functionality  

NASA Astrophysics Data System (ADS)

Each year in the United States there is an increasing trend of patients receiving total joint replacement (TJR) procedures. Approximately a half million total knee replacements (TKRs) are performed annually in the United States with increasing prevalence attributed to baby-boomers, obesity, older, and younger patients. This trend is also seen for total hip replacements (THRs) as well. The use of ultra high molecular weight polyethylene (UHMWPE) inserts in TJRs results in wear particle-induced osteolysis, which is the predominant cause for prosthesis failure and revision surgery. Sub-micron size particle generation is inevitable despite the numerous efforts in improving this bearing material. Work by others has shown that the use of oral and intravenous systemic bisphosphonates (BP) can significantly minimize periprosthetic osteolysis. However, the systemic delivery and the high solubility of BPs results in a predominant portion of the drug being excreted via the kidney without reaching its target, bone. This doctoral research project is focused on the development and evaluation of a novel method to administer BPs locally using the inherent wear of UHMWPE for possible use as an anti-osteolysis treatment. For new materials to be considered, they must be mechanically and tribologically comparable to the current gold standard, UHMWPE. In order to evaluate this material, mechanical, drug elution and tribological experiments were performed to allow assessment of material properties. Tensile tests showed comparable yield stress and pin-on-disk testing showed comparable wear to standard virgin UHMWPE. Further, drug elution tests have shown that BP was released from the enriched material both in static and dynamic conditions. Additionally, an aggressive 2 million cycle total knee simulator experiment has shown statistically similar wear results for the two materials. Overall, this research has provided the groundwork for further characterization and development of a new potential material for total joint replacements as an enhancement to standard UHMWPE. This material shows significant potential as an alternative bearing material to indirectly increase TJR longevity by addressing osteolysis related issues.

Wright-Walker, Cassandra Jane

71

The Independent and Interactive Effects of Navicular Drop and Quadriceps Angle on Neuromuscular Responses to a Weight-Bearing Perturbation with COMMENTARY and AUTHORS' RESPONSE  

Microsoft Academic Search

***Note: Figures may be missing from this format of the document Abstract: Little is known about the effects of static alignment on neuromuscular control of the knee during dynamic motion. To evaluate the isolated and combined effects of quadriceps angle (QA) and navicular drop (ND) on neuromuscular responses to a weight-bearing perturbation. Mixed- model, repeated-measures design. Sports medicine and athletic

Sandra J Shultz; Christopher R Carcia; Bruce M Gansneder; David H Perrin; Glenn N

72

Multidirectional transparent support for overground gait training.  

PubMed

Gait and balance training is an essential ingredient for locomotor rehabilitation of patients with neurological impairments. Robotic overhead support systems may help these patients train, for example by relieving them of part of their body weight. However, there are only very few systems that provide support during overground gait, and these suffer from limited degrees of freedom and/or undesired interaction forces due to uncompensated robot dynamics, namely inertia. Here, we suggest a novel mechanical concept that is based on cable robot technology and that allows three-dimensional gait training while reducing apparent robot dynamics to a minimum. The solution does not suffer from the conventional drawback of cable robots, which is a limited workspace. Instead, displaceable deflection units follow the human subject above a large walking area. These deflection units are not actuated, instead they are implicitly displaced by means of the forces in the cables they deflect. This leads to an underactuated design, because the deflection units cannot be moved arbitrarily. However, the design still allows accurate control of a three-dimensional force vector acting on a human subject during gait. We describe the mechanical concept, the control concept, and we show first experimental results obtained with the device, including the force control performance during robot-supported overground gait of five human subjects without motor impairments. PMID:24187327

Vallery, H; Lutz, P; von Zitzewitz, J; Rauter, G; Fritschi, M; Everarts, C; Ronsse, R; Curt, A; Bolliger, M

2013-06-01

73

A palmar pressure sensor for measurement of upper limb weight bearing by the hands during transfers by paraplegics.  

PubMed

Paraplegic patients have to effect transfer from one seat to another by using their upper limbs. In this process the hands bear almost the entire weight of the body in at least some phases of the transfer. It is desirable to train patients, especially those who are elderly and otherwise weak, to distribute their weight so as to avoid large forces being sustained on any one hand for an extended period. It is also desirable to evaluate the effectiveness of assistive devices like lower limb FES in sharing the load on the hand. This study presents a simple and versatile method of measuring palmar hand force during transfers by paraplegic patients. It is important that this force sensor should not interfere with the grasping and stabilizing properties of the hands and should permit normal transferring. The force sensor comprises an air-filled pouch or pillow that can be placed on any surface. This pneumatic sensor feels like upholstery padding on the surface on which it is placed. The sensor integrates the total pressure applied to the surface of the pouch, thereby obtaining the total force exerted by the palm/hand. The fabrication of the sensor is described, as well as the associated measurement circuit. The static calibration shows that the sensor is linear up to 350?N and the dynamic calibration shows that it has a bandwidth of 13?Hz. The sensor was fabricated using an inflated inelastic airbag attached to a pressure transducer. An automatic offset correction circuit in the preamplifier module ensures that any offset due to initial pressure or sensor drift is removed and the output is zero under no load condition. The key to this sensor arrangement is the ease of fitting it into the intended location without disturbing the existing arrangement for the subject's activities of daily living (ADL). PMID:23964668

Kunju, Nissan; Ojha, Rajdeep; Devasahayam, Suresh R

2013-10-01

74

Multistimuli-responsive supramolecular organogels formed by low-molecular-weight peptides bearing side-chain azobenzene moieties.  

PubMed

This work demonstrates that the incorporation of azobenzene residues into the side chain of low-molecular-weight peptides can modulate their self-assembly process in organic solvents leading to the formation of stimuli responsive physical organogels. The major driving forces for the gelation process are hydrogen bonding and ?-? interactions, which can be triggered either by thermal or ultrasound external stimuli, affording materials having virtually the same properties. In addition, a predictive model for gelation of polar protic solvent was developed by using Kamlet-Taft solvent parameters and experimental data. The obtained viscoelastic materials exhibited interconnected multistimuli responsive behaviors including thermal-, photo-, chemo- and mechanical responses. All of them displayed thermoreversability with gel-to-sol transition temperatures established between 33-80 °C and gelation times from minutes to several hours. Structure-property relationship studies of a designed peptide library have demonstrated that the presence and position of the azobenzene residue can be operated as a versatile regulator to reduce the critical gelation concentration and enhance both the thermal stability and mechanical strength of the gels, as demonstrated by comparative dynamic rheology. The presence of N-Boc protecting group in the peptides showed also a remarkable effect on the formation and properties of the gels. Despite numerous examples of peptide-based gelators known in the literature, this is the first time in which low-molecular-weight peptides bearing side chain azobenzene units are used for the synthesis of "intelligent" supramolecular organogels. Compared with other approaches, this strategy is advantageous in terms of structural flexibility since it is compatible with a free, unprotected amino terminus and allows placement of the chromophore at any position of the peptide sequence. PMID:23704042

Fatás, Paola; Bachl, Jürgen; Oehm, Stefan; Jiménez, Ana I; Cativiela, Carlos; Díaz Díaz, David

2013-07-01

75

Importance of Gait Training  

MedlinePLUS

... all lower-limb amputees will bene?t from gait training at some point in their recovery to help ... the supervision of a physical therapist, the initial training is provided by the prosthetist as part of ...

76

Weight-bearing asymmetries during Sit-To-Stand in patients with mild-to-moderate hip osteoarthritis.  

PubMed

The Sit-To-Stand (STS) transition is a mechanically demanding task that may pose particular challenges for individuals with lower limb osteoarthritis (OA). Biomechanical features of STS have been investigated in patients with OA, but not in patients with early stage hip OA. The purpose of this study was to explore inter-limb weight-bearing asymmetries (WBA) and selected kinematic and kinetic variables during STS in patients with mild-to-moderate hip OA compared with healthy controls. Twenty-one hip OA patients and 23 controls were included in the study. Sagittal and frontal plane kinematic and kinetic data were collected using an eight-camera motion analysis system synchronized with two force plates embedded in the floor. There were no distinctive biomechanical alterations in sagittal or frontal plane kinematics or kinetics, movement time, or time to reach peak ground reaction force (GRF) in hip OA patients compared with controls. However, the hip OA patients revealed a distinct pattern of WBA compared with the controls, in unloading their involved limb by 18.4% at peak GRF. These findings indicate that patients with early stage hip OA are not yet forced into a stereotypical movement strategy for STS; however, the observed pattern of WBA requires clinical attention. PMID:24238750

Eitzen, Ingrid; Fernandes, Linda; Nordsletten, Lars; Snyder-Mackler, Lynn; Risberg, May Arna

2014-02-01

77

Phasic-to-tonic shift in trunk muscle activity relative to walking during low-impact weight bearing exercise  

NASA Astrophysics Data System (ADS)

The aim of this study was to investigate the influence of an exercise device, designed to improve the function of lumbopelvic muscles via low-impact weight-bearing exercise, on electromyographic (EMG) activity of lumbopelvic, including abdominal muscles. Surface EMG activity was collected from lumbar multifidus (LM), erector spinae (ES), internal oblique (IO), external oblique (EO) and rectus abdominis (RA) during overground walking (OW) and exercise device (EX) conditions. During walking, most muscles showed peaks in activity which were not seen during EX. Spinal extensors (LM, ES) were more active in EX. Internal oblique and RA were less active in EX. In EX, LM and ES were active for longer than during OW. Conversely, EO and RA were active for a shorter duration in EX than OW. The exercise device showed a phasic-to-tonic shift in activation of both local and global lumbopelvic muscles and promoted increased activation of spinal extensors in relation to walking. These features could make the exercise device a useful rehabilitative tool for populations with lumbopelvic muscle atrophy and dysfunction, including those recovering from deconditioning due to long-term bed rest and microgravity in astronauts.

Caplan, Nick; Gibbon, Karl; Hibbs, Angela; Evetts, Simon; Debuse, Dorothée

2014-11-01

78

A Robot and Control Algorithm That Can Synchronously Assist in Naturalistic Motion During Body-Weight-Supported Gait Training Following Neurologic Injury  

Microsoft Academic Search

Locomotor training using body weight support on a treadmill and manual assistance is a promising rehabilitation technique following neurological injuries, such as spinal cord injury (SCI) and stroke. Previous robots that automate this technique impose constraints on naturalistic walking due to their kinematic structure, and are typically operated in a stiff mode, limiting the ability of the patient or human

Daisuke Aoyagi; Wade E. Ichinose; Susan J. Harkema; David J. Reinkensmeyer; James E. Bobrow

2007-01-01

79

Gait and its assessment in psychiatry  

PubMed Central

Gait reflects all levels of nervous system function. In psychiatry, gait disturbances reflecting cortical and subcortical dysfunction are often seen. Observing spontaneous gait, sometimes augmented by a few brief tests, can be highly informative. The authors briefly review the neuroanatomy of gait, review gait abnormalities seen in psychiatric and neurologic disorders, and describe the assessment of gait. PMID:20805918

Sanders, Richard D.

2010-01-01

80

Prediction of scratch resistance of cobalt chromium alloy bearing surface, articulating against ultra-high molecular weight polyethylene, due to third-body wear particles.  

PubMed

The entrapment of abrasive particles within the articulation between a cobalt chromium alloy (CoCrMo) femoral component and an ultra-high molecular weight polyethylene (UHMWPE) cup of artificial hip joints or tibial inserts of artificial knee joints usually scratches the metallic bearing surface and consequently increases the surface roughness. This has been recognized as one of the main causes of excessive polyethylene wear, leading to osteolysis and loosening of the prosthetic components. The purpose of this study was to use the finite element method to investigate the resistance of the cobalt chromium alloy bearing surface to plastic deformation, as a first approximation to causing scratches, due to various entrapped debris such as bone, CoCrMo and ZrO2 (contained in radiopaque polymethyl methacrylate cement). A simple axisymmetric micro contact mechanics model was developed, where a spherical third-body wear particle was indented between the two bearing surfaces, modelled as two solid cylinders of a given diameter, under the contact pressure determined from macro-models representing either hip or knee implants. The deformation of both the wear particle and the bearing surfaces was modelled and was treated as elastic-plastic. The indented peak-to-valley height on the CoCrMo bearing surface from the finite element model was found to be in good agreement with that reported in a previous study when the third-body wear particle was assumed to be rigid. Under the physiological contact pressure experienced in both hip and knee implants, ZrO2 wear particles were found to be fully embedded within the UHMWPE bearing surface, and the maximum von Mises stresses within the CoCrMo bearing surface reached the corresponding yield strength. Consequently, the CoCrMo bearing surface was deformed plastically and the corresponding peak-to-valley height (surface roughness) was found to increase with both the hardness and the size of the wear particle. Even in the case of CoCrMo wear particles, with similar mechanical properties to those of the CoCrMo bearing surface, a significant plastic deformation of the bearing surface was also noted; this highlighted the importance of considering the deformation of the wear particles. These findings support the hypotheses made by clinical studies on the contribution of entrapped debris to increased surface roughness of CoCrMo femoral bearing surfaces. PMID:14982345

Mirghany, M; Jin, Z M

2004-01-01

81

Ground reaction forces and plantar pressure distribution during occasional loaded gait.  

PubMed

This study compared the ground reaction forces (GRF) and plantar pressures between unloaded and occasional loaded gait. The GRF and plantar pressures of 60 participants were recorded during unloaded gait and occasional loaded gait (wearing a backpack that raised their body mass index to 30); this load criterion was adopted because is considered potentially harmful in permanent loaded gait (obese people). The results indicate an overall increase (absolute values) of GRF and plantar pressures during occasional loaded gait (p < 0.05); also, higher normalized (by total weight) values in the medial midfoot and toes, and lower values in the lateral rearfoot region were observed. During loaded gait the magnitude of the vertical GRF (impact and thrust maximum) decreased and the shear forces increased more than did the proportion of the load (normalized values). These data suggest a different pattern of GRF and plantar pressure distribution during occasional loaded compared to unloaded gait. PMID:23157973

Castro, Marcelo; Abreu, Sofia; Sousa, Helena; Machado, Leandro; Santos, Rubim; Vilas-Boas, João Paulo

2013-05-01

82

Context based gait recognition  

NASA Astrophysics Data System (ADS)

Gait recognition has recently become a popular topic in the field of biometrics. However, the main hurdle is the insufficient recognition rate in the presence of low quality samples. The main focus of this paper is to investigate how the performance of a gait recognition system can be improved using additional information about behavioral patterns of users and the context in which samples have been taken. The obtained results show combining the context information with biometric data improves the performance of the system at a very low cost. The amount of improvement depends on the distinctiveness of the behavioral patterns and the quality of the gait samples. Using the appropriate distinctive behavioral models it is possible to achieve a 100% recognition rate.

Bazazian, Shermin; Gavrilova, Marina

2012-06-01

83

Radiographic and functional results in the treatment of early stages of Charcot neuroarthropathy with a walker boot and immediate weight bearing  

PubMed Central

Background One of the most common gold standards for the treatment of Charcot neuroarthropathy (CN) in the early Eichenholtz stages I and II is immobilization with the total contact casting and lower limb offloading. However, the total amount of offloading is still debatable. Objectives This study evaluates the clinical and radiographic findings in the treatment of early stages of CN (Eichenholtz stages I and II) with a walker boot and immediate total weight-bearing status. Methods Twenty-two patients with type 2 diabetes mellitus (DM) and CN of Eichenholtz stages I and II were selected for non-operative treatment. All patients were educated about their condition, and full weight bearing was allowed as tolerated. Patients were monitored on a fortnightly basis in the earlier stages, with clinical examination, temperature measurement, and standardized weight-bearing radiographs. Their American Orthopedic Foot and Ankle Society (AOFAS) scores were determined before and after the treatment protocol. Results No cutaneous ulcerations or infections were observed in the evaluated cases. The mean measured angles at the beginning and end of the study, although showing relative increase, did not present a statistically significant difference (p > 0.05). Mean AOFAS scores showed a statistically significant improvement by the end of the study (p < 0.005). Conclusion The treatment of early stages of CN (Eichenholtz stages I and II) with emphasis on walker boot and immediate weight bearing has shown a good functional outcome, non-progressive deformity on radiographic assessment, and promising results as a safe treatment option. PMID:24179634

Parisi, Maria Candida Ribeiro; Godoy-Santos, Alexandre Leme; Ortiz, Rafael Trevisan; Sposeto, Rafael Barban; Sakaki, Marcos Hideyo; Nery, Marcia; Fernandes, Tulio Diniz

2013-01-01

84

The analysis on period doubling gait and chaotic gait of the compass-gait biped model  

Microsoft Academic Search

The passive dynamic walking model, which can only depend on the gravity and its own inertia, presents stable, high-efficient, natural periodic gait on a slight slope. The stable periodic gait of the robot has a delicate balance of energy conversion, which makes the gait adjust itself as the parameters of the model change. In our work, the cell mapping method

Jie Zhao; Xiaoguang Wu; Xizhe Zang; Yanhe Zhu; Lei Zhu

2011-01-01

85

An in vivo study of hindfoot 3D kinetics in stage II posterior tibial tendon dysfunction (PTTD) flatfoot based on weight-bearing CT scan  

PubMed Central

Objective The objective of this study was to evaluate the rotation and translation of each joint in the hindfoot and compare the load response in healthy feet with that in stage II posterior tibial tendon dysfunction (PTTD) flatfoot by analysing the reconstructive three-dimensional (3D) computed tomography (CT) image data during simulated weight-bearing. Methods CT scans of 15 healthy feet and 15 feet with stage II PTTD flatfoot were taken first in a non-weight-bearing condition, followed by a simulated full-body weight-bearing condition. The images of the hindfoot bones were reconstructed into 3D models. The ‘twice registration’ method in three planes was used to calculate the position of the talus relative to the calcaneus in the talocalcaneal joint, the navicular relative to the talus in talonavicular joint, and the cuboid relative to the calcaneus in the calcaneocuboid joint. Results From non- to full-body-weight-bearing condition, the difference in the talus position relative to the calcaneus in the talocalcaneal joint was 0.6° more dorsiflexed (p = 0.032), 1.4° more everted (p = 0.026), 0.9 mm more anterior (p = 0.031) and 1.0 mm more proximal (p = 0.004) in stage II PTTD flatfoot compared with that in a healthy foot. The navicular position difference relative to the talus in the talonavicular joint was 3° more everted (p = 0.012), 1.3 mm more lateral (p = 0.024), 0.8 mm more anterior (p = 0.037) and 2.1 mm more proximal (p = 0.017). The cuboid position difference relative to the calcaneus in the calcaneocuboid joint did not change significantly in rotation and translation (all p ? 0.08). Conclusion Referring to a previous study regarding both the cadaveric foot and the live foot, joint instability occurred in the hindfoot in simulated weight-bearing condition in patients with stage II PTTD flatfoot. The method used in this study might be applied to clinical analysis of the aetiology and evolution of PTTD flatfoot, and may inform biomechanical analyses of the effects of foot surgery in the future. Cite this article: Bone Joint Res 2013;2:255–63. PMID:24324193

Zhang, Y.; Xu, J.; Wang, X.; Huang, J.; Zhang, C.; Chen, L.; Wang, C.; Ma, X.

2013-01-01

86

Pelvic control and over-ground walking methodology for impaired gait recovery  

Microsoft Academic Search

In this paper, a methodology for gait rehabilitation, combines over-ground walking, body weight support, pelvic control, and gait assistance are introduced and the integrated platform has been developed. This paper also discusses the gap of state-of-the-art research in gait rehabilitation. Systems like Lokomat and Kineassist were studied and discussed. Initial testing and EMG experiments have been carried out on the

H. B. Lim; K. H. Hoon; K. H. Low; Y. C. Soh; A. Tow

2009-01-01

87

Magnetic Bearing  

NASA Technical Reports Server (NTRS)

AVCON, Inc. produces advanced magnetic bearing systems for industrial use, offering a unique technological approach based on contract work done at Marshall Space Flight Center and Lewis Research Center. Designed for the turbopump of the Space Shuttle main engine, they are now used in applications such as electric power generation, petroleum refining, machine tool operation and natural gas pipelines. Magnetic bearings support moving machinery without physical contact; AVCON's homopolar approach is a hybrid of permanent and electromagnets which are one-third the weight, smaller and more power- efficient than previous magnetic bearings.

1996-01-01

88

Gait Stability following Concussion  

Microsoft Academic Search

PARKER, T. M., L. R. OSTERNIG, P. VAN DONKELAAR, and L. CHOU. Gait Stability following Concussion. Med. Sci. Sports Exerc., Vol. 38, No. 6, pp. 1032 - 1040, 2006. Introduction: The need to identify functional impairment following a brain injury is critical to prevent reinjury during the period of recovery. However, little is known about the effect of concussion on

TONYA M. PARKER; LOUIS R. OSTERNIG; PAUL VAN DONKELAAR; LI-SHAN CHOU

2006-01-01

89

Gait-locomotor apparatus  

US Patent & Trademark Office Database

The gait-locomotor apparatus of the present invention is a device for overcoming impeded locomotion in humans and is aimed at enabling people with handicapped lower limbs to walk. The gait-locomotor apparatus that is wore on a disabled user comprises a brace having a plurality of jointed segments that are adapted to fit the lower body of the disabled user and propulsion means that is adapted to provide relative movement between the plurality of jointed segments. The gait-locomotor apparatus further comprises at least one sensor adapted to monitor the angular position of at least one of the plurality of jointed segments and a control unit that is adapted to supervise the propulsion means and to receive feedback information from the sensors so as to facilitate the brace to perform walking patterns. The disabled user that wears the gait-locomotor apparatus of the present invention is able to steadily stand in a stance position supported by the brace, and is able to walk in various walking patterns using the control unit while fully participating in the process.

2006-12-26

90

Visual analysis of the effects of load carriage on gait  

NASA Astrophysics Data System (ADS)

As early as the 1970's it was determined that gait, or the "manner of walking" is an identifying feature of a human being. Since then, extensive research has been done in the field of computer vision to determine how accurately a subject can be identified by gait characteristics. This has necessarily led to the study of how various data collection conditions, such as terrain type, varying camera angles, or a carried briefcase, may affect the identifying features of gait. However, little or no research has been done to question whether such conditions may be inferred from gait analysis. For example, is it possible to determine characteristics of the walking surface simply by looking at statistics derived from the subject's gait? The question to be addressed is whether significant concealed weight distributed on the subject's torso can be discovered through analysis of his gait. Individual trends in subjects in response to increasing concealed weight will be explored, with the objective of finding universal trends that would have obvious security purposes.

Wittman, Michael G.; Ward, James M.; Flynn, Patrick J.

2005-03-01

91

Evaluation of knee joint muscle forces and tissue stresses-strains during gait in severe OA versus normal subjects.  

PubMed

Osteoarthritis (OA) is the leading cause of pain and disability in the elderly with the knee being the most affected weight bearing joint. We used a musculoskeletal biomechanical model of the lower extremity including a detailed validated knee joint finite element model to compute lower extremity muscle forces and knee joint stresses-strains during the stance phase of gait. The model was driven by gait data on OA patients, and results were compared with those of the same model driven by data on normal controls. Additional analyses were performed with altered cartilage-menisci properties to evaluate the effects of deterioration during OA. In OA patients compared to normal subjects, muscle forces dropped at nearly all stance periods except mid-stance. Force in the anterior cruciate ligament remained overall the same. Total contact forces-stresses deceased by about 25%. Alterations in properties due to OA had negligible effects on muscle forces, but increased contact areas and cartilage strains and reduced contact pressures. Reductions in contact stresses and increases in tissue strains and transfer of load via menisci are partly due to the altered kinetics-kinematics of gait and partly due to deterioration in cartilage-menisci properties in OA patients. PMID:24038150

Adouni, M; Shirazi-Adl, A

2014-01-01

92

Spoof Attacks on Gait Authentication System  

Microsoft Academic Search

Research in biometric gait recognition has increased. Earlier gait recognition works reported promising results, usually with a small sample size. Recent studies with a larger sample size confirm gait potential as a biometric from which individuals can be identified. Despite much research being carried out in gait recognition, the topic of vulnerability of gait to attacks has not received enough

Davrondzhon Gafurov; Einar Snekkenes; Patrick A. H. Bours

2007-01-01

93

Effect of Weight-bearing Therapeutic Exercise on the Q-angle and Muscle Activity Onset Times of Elite Athletes with Patellofemoral Pain Syndrome: A Randomized Controlled Trial  

PubMed Central

[Purpose] The purpose of this study was to determine the effect of a weight-bearing therapeutic exercise program for elite athletes diagnosed as having patellofemoral pain syndrome (PFPS). [Subjects] The subjects were 34 elite athletes from the Seoul T Center. They were randomly allocated to three groups: an elastic band exercise group (EBG), a sling exercise group (SEG), or a control group (CG). [Methods] Therapeutic exercises were performed 3 times a week for 8 weeks. The visual analogue scale (VAS) hamstring length, and static and dynamic Q angles were used to test the exercise effect of the exercises, as well as the onset time of electromyographic activity of vastus medialis oblique (VMO) and vastus lateralis (VL). [Results] Decrease of the dynamic Q-angle in EBG was significant and significantly greater than that in CG. The decrease in VAS in SEG was significant and significantly greater than that in CG. There were significant differences in the VL and VMO activity onset times in SEG between pre- and post-test, and their differences between pre- and post-test were also significantly different. [Conclusion] Weight-bearing therapeutic exercise is hoped that clinicians will use this information for better implementation of effective exercise methods for elite athletes with PFPS. PMID:25140080

Lee, Jehoon; Lee, Hwangjae; Lee, Wanhee

2014-01-01

94

In vivo regulation of the beta-myosin heavy chain gene in soleus muscle of suspended and weight-bearing rats  

NASA Technical Reports Server (NTRS)

In the weight-bearing hindlimb soleus muscle of the rat, approximately 90% of muscle fibers express the beta-myosin heavy chain (beta-MHC) isoform protein. Hindlimb suspension (HS) causes the MHC isoform population to shift from beta toward the fast MHC isoforms. Our aim was to establish a model to test the hypothesis that this shift in expression is transcriptionally regulated through specific cis elements of the beta-MHC promoter. With the use of a direct gene transfer approach, we determined the activity of different length beta-MHC promoter fragments, linked to a firefly luciferase reporter gene, in soleus muscle of control and HS rats. In weight-bearing rats, the relative luciferase activity of the longest beta-promoter fragment (-3500 bp) was threefold higher than the shorter promoter constructs, which suggests that an enhancer sequence is present in the upstream promoter region. After 1 wk of HS, the reporter activities of the -3500-, -914-, and -408-bp promoter constructs were significantly reduced ( approximately 40%), compared with the control muscles. However, using the -215-bp construct, no differences in promoter activity were observed between HS and control muscles, which indicates that the response to HS in the rodent appears to be regulated within the -408 and -215 bp of the promoter.

Giger, J. M.; Haddad, F.; Qin, A. X.; Baldwin, K. M.

2000-01-01

95

Biofeedback for robotic gait rehabilitation  

Microsoft Academic Search

BACKGROUND: Development and increasing acceptance of rehabilitation robots as well as advances in technology allow new forms of therapy for patients with neurological disorders. Robot-assisted gait therapy can increase the training duration and the intensity for the patients while reducing the physical strain for the therapist. Optimal training effects during gait therapy generally depend on appropriate feedback about performance. Compared

Lars Lünenburger; Gery Colombo; Robert Riener

2007-01-01

96

Gait analysis methods in rehabilitation  

Microsoft Academic Search

INTRODUCTION: Brand's four reasons for clinical tests and his analysis of the characteristics of valid biomechanical tests for use in orthopaedics are taken as a basis for determining what methodologies are required for gait analysis in a clinical rehabilitation context. MEASUREMENT METHODS IN CLINICAL GAIT ANALYSIS: The state of the art of optical systems capable of measuring the positions of

Richard Baker; Hugh Williamson; Gait CCRE

2006-01-01

97

Gait Recognition and Walking Exercise Intensity Estimation  

PubMed Central

Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients’ exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, ?? filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD) was used to filter the noise of patients’ attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study. PMID:24714057

Lin, Bor-Shing; Liu, Yu-Ting; Yu, Chu; Jan, Gene Eu; Hsiao, Bo-Tang

2014-01-01

98

Gait recognition and walking exercise intensity estimation.  

PubMed

Cardiovascular patients consult doctors for advice regarding regular exercise, whereas obese patients must self-manage their weight. Because a system for permanently monitoring and tracking patients' exercise intensities and workouts is necessary, a system for recognizing gait and estimating walking exercise intensity was proposed. For gait recognition analysis, ?? filters were used to improve the recognition of athletic attitude. Furthermore, empirical mode decomposition (EMD) was used to filter the noise of patients' attitude to acquire the Fourier transform energy spectrum. Linear discriminant analysis was then applied to this energy spectrum for training and recognition. When the gait or motion was recognized, the walking exercise intensity was estimated. In addition, this study addressed the correlation between inertia and exercise intensity by using the residual function of the EMD and quadratic approximation to filter the effect of the baseline drift integral of the acceleration sensor. The increase in the determination coefficient of the regression equation from 0.55 to 0.81 proved that the accuracy of the method for estimating walking exercise intensity proposed by Kurihara was improved in this study. PMID:24714057

Lin, Bor-Shing; Liu, Yu-Ting; Yu, Chu; Jan, Gene Eu; Hsiao, Bo-Tang

2014-04-01

99

Effective one step-iterative fiducial marker-based compensation for involuntary motion in weight-bearing C-arm cone-beam CT scanning of knees  

NASA Astrophysics Data System (ADS)

We previously introduced three different fiducial marker-based correction methods (2D projection shifting, 2D projection warping, and 3D image warping) for patients' involuntary motion in the lower body during weight-bearing Carm CT scanning. The 3D warping method performed better than 2D methods since it could more accurately take into account the lower body motion in 3D. However, as the 3D warping method applies different rotational and translational movement to the reconstructed image for each projection frame, distance-related weightings were slightly twisted and thus result in overlaying background noise over the entire image. In order to suppress background noise and artifacts (e.g. metallic marker-caused streaks), the 3D warping method has been improved by incorporating bilateral filtering and a Landwebertype iteration in one step. A series of projection images of five healthy volunteers standing at various flexion angles were acquired using a C-arm cone-beam CT system with a flat panel. A horizontal scanning trajectory of the C-arm was calibrated to generate projection matrices. Using the projection matrices, the static reference marker coordinates in 3D were estimated and used for the improved 3D warping method. The improved 3D warping method effectively reduced background noise down below the noise level of 2D methods and also eliminated metal-generated streaks. Thus, improved visibility of soft tissue structures (e.g. fat and muscle) was achieved while maintaining sharp edges at bone-tissue interfaces. Any high resolution weight-bearing cone-beam CT system can apply this method for motion compensation.

Choi, Jang-Hwan; Maier, Andreas; Berger, Martin; Fahrig, Rebecca

2014-03-01

100

METACHRONAL WAVE GAIT GENERATION FOR HEXAPOD ROBOTS  

E-print Network

METACHRONAL WAVE GAIT GENERATION FOR HEXAPOD ROBOTS GARY B. PARKER and JONATHAN W. MILLS Department: genetic, robot, hexapod, gait, control, cyclic, metachronal INTRODUCTION Generating gaits is important have been used to evolve gaits for hexapod robots. Those striving for maximum speed have been used

Parker, Gary B.

101

Growth hormone, IGF-I, and exercise effects on non-weight-bearing fast muscles of hypophysectomized rats  

NASA Technical Reports Server (NTRS)

The effects of growth hormone (GH) or insulin-like growth factor I (IGF-I) with or without exercise (ladder climbing) in countering the effects of unweighting on fast muscles of hypophysectomized rats during 10 days of hindlimb suspension were determined. Compared with untreated suspended rats, muscle weights were 16-29% larger in GH-treated and 5-15% larger in IGF-I-treated suspended rats. Exercise alone had no effect on muscle weights. Compared with ambulatory control, the medial gastrocnemius weight in suspended, exercised rats was larger after GH treatment and maintained with IGF-I treatment. The combination of GH or IGF-I plus exercise in suspended rats resulted in an increase in size of each predominant fiber type, i.e., types I, I + IIa and IIa + IIx, in the medial gastrocnemius compared with untreated suspended rats. Normal ambulation or exercise during suspension increased the proportion of fibers expressing embryonic myosin heavy chain in hypophysectomized rats. The phenotype of the medial gastrocnemius was minimally affected by GH, IGF-I, and/or exercise. These results show that there is an IGF-I, as well as a GH, and exercise interactive effect in maintaining medial gastrocnemius fiber size in suspended hypophysectomized rats.

Grossman, E. J.; Grindeland, R. E.; Roy, R. R.; Talmadge, R. J.; Evans, J.; Edgerton, V. R.

1997-01-01

102

Gait Disturbances in Dystrophic Hamsters  

PubMed Central

The delta-sarcoglycan-deficient hamster is an excellent model to study muscular dystrophy. Gait disturbances, important clinically, have not been described in this animal model. We applied ventral plane videography (DigiGait) to analyze gait in BIO TO-2 dystrophic and BIO F1B control hamsters walking on a transparent treadmill belt. Stride length was ?13% shorter (P < .05) in TO-2 hamsters at 9 months of age compared to F1B hamsters. Hindlimb propulsion duration, an indicator of muscle strength, was shorter in 9-month-old TO-2 (247 ± 8?ms) compared to F1B hamsters (272 ± 11?ms; P < .05). Braking duration, reflecting generation of ground reaction forces, was delayed in 9-month-old TO-2 (147 ± 6?ms) compared to F1B hamsters (126 ± 8?ms; P < .05). Hindpaw eversion, evidence of muscle weakness, was greater in 9-month-old TO-2 than in F1B hamsters (17.7 ± 1.2° versus 8.7 ± 1.6°; P < .05). Incline and decline walking aggravated gait disturbances in TO-2 hamsters at 3 months of age. Several gait deficits were apparent in TO-2 hamsters at 1 month of age. Quantitative gait analysis demonstrates that dystrophic TO-2 hamsters recapitulate functional aspects of human muscular dystrophy. Early detection of gait abnormalities in a convenient animal model may accelerate the development of therapies for muscular dystrophy. PMID:21318074

Hampton, Thomas G.; Kale, Ajit; Amende, Ivo; Tang, Wenlong; McCue, Scott; Bhagavan, Hemmi N.; VanDongen, Case G.

2011-01-01

103

A reliable gait phase detection system  

Microsoft Academic Search

A new highly reliable gait phase detection system, which can be used in gait analysis applications and to control the gait cycle of a neuroprosthesis for walking, is described. The system was designed to detect in real-time the following gait phases: stance, heel-off, swing, and heel-strike. The gait phase detection system employed a gyroscope to measure the angular velocity of

I. P. I. Pappas; M. R. Popovic; T. Keller; V. Dietz; M. Morari

2001-01-01

104

Premotor cortex is involved in restoration of gait in stroke.  

PubMed

Cortical activation during hemiplegic gait was assessed in six nonambulatory patients with severe stroke (four men, two women; four with right and two with left hemiplegia; 57 years old and 3 months after stroke on average), using a near-infrared spectroscopic imaging system. Each patient performed tasks of treadmill walking (0.2km/hr), alternated with rest every 30 seconds for four repetitions, under partial body weight support, either with mechanical assistance in swinging the paretic leg control (CON) or with a facilitation technique that enhanced swinging of the paretic leg (FT), provided by physical therapists. Gait performance was associated with increased oxygenated hemoglobin levels in the medial primary sensorimotor cortex in the unaffected hemisphere greater than in the affected hemisphere. Both cortical mappings and quantitative data showed that the premotor activation in the affected hemisphere was enhanced during hemiplegic gait. There was also a prominent activation in the presupplementary motor area. Overall cortical activations and gait performance were greater in walking with FT than with CON. These indicate that multiple motor areas including the premotor cortex and presupplementary motor area might play important roles in restoration of gait in patients with severe stroke. PMID:12210789

Miyai, Ichiro; Yagura, Hajime; Oda, Ichiro; Konishi, Ikuo; Eda, Hideo; Suzuki, Tsunehiko; Kubota, Kisou

2002-08-01

105

Gait Changes Caused by the Habits and Methods of Carrying a Handbag  

PubMed Central

[Purpose] The purpose of this study was to provide information to help maintain correct posture by identifying gait changes caused by the habits and methods of carrying bags. [Method] The subjects were 34 healthy right-handed women. Among them, 18 subjects had the habit of carrying bags on their right side, and 16 subjects had the habit of carrying bags on their left side. The subjects were instructed to walk while carrying a bag, which weighted approximately 10% of the subjects' average weight, in four different ways; holding it in the left hand, carrying it over the left shoulder, holding it in the right hand, and carrying it over the right shoulder. The subjects' gaits were measured using a gait analyzer. [Results] Subjects who habitually carried bags on their right exhibited changes in gait variables related to walking distance. In addition, their gait velocities were relatively faster. On the other hand, differences in temporal and spatial gait variables were not exhibited when the bag was carried using the four methods. [Conclusion] When the weight of a bag is appropriate, bag-carrying habits had significant effects on gaits. Therefore, people who carry bags should avoid the habit of carrying them on only one side. PMID:24259895

Son, SungMin; Noh, Hyolyun

2013-01-01

106

A robot for gait rehabilitation  

E-print Network

After a stroke, persons suffer from neurological impairments that affect gait, and so require rehabilitation to regain ambulatory function. While 82% of patients recover the ability to walk, current methods including ...

Roberts, Michael (Michael Henry), 1980-

2004-01-01

107

Methods of running gait analysis.  

PubMed

The continued increase in running popularity has led to a subsequent increase in the need to assess running gait more easily and affordably. Although traditional measurement devices such as motion capture systems, force plates, and electromyography are adequate methods of gait analysis, they suffer from several limitations, such as expense and lack of portability. Recent technological advances have made available more viable options such as accelerometers, electrogoniometers, gyroscopes, and in-shoe pressure sensors. These sensors are being used more commonly to acquire the same information as the more traditional systems, without the associated limitations. Combined with wireless technology and/or data loggers, they provide an affordable, lightweight alternative to gait analysis, allowing data collection over prolonged periods of time in almost any environment. This article will review the current technologies used in the analysis of running gait, with a focus upon the latest developments and equipment. PMID:19436169

Higginson, Brian K

2009-01-01

108

Gait analysis before and after unilateral total knee arthroplasty. Study using a linear regression model of normal controls — women without arthropathy  

Microsoft Academic Search

:   Stepwise multiple regression analysis (forward method) was performed with 22 gait variables obtained from the free and slow\\u000a gait of 35 normal controls (women without knee arthropathy). These 22 variables were target variables, and velocity, age,\\u000a body height, and body weight were explanatory variables. Velocity showed the greatest effect on the gait variables, followed\\u000a by weight, age, and height.

Tae Hyun Lee; Tomitsu Tsuchida; Hiroshi Kitahara; Hideshige Moriya

1999-01-01

109

Patient-specific walking pattern simulation in a gait trajectory guiding device.  

PubMed

Repetitive training is of much importance for restoring full-fledged gait ability. At present, task-specific repetitive approach has been proved to be the most effective motor learning concept. In this regard, a gait trajectory guiding device with partial body weight support system can be a solution for gait rehabilitation. This paper presents a complete gait study with an objective to implement the motion of a natural walking pattern in the automated foot-boards of a gait trajectory guiding device. In our developed motion algorithm of foot-boards we have concentrated on adaptation of patient-specific true walking trajectory, determination of variable velocity pattern along different degrees of freedom and time-division for simulating different phases of a complete gait cycle. Gait database, collected from disparate sources and previous gait-studies have been used for kinetic and kinematic analysis of human walking. We have modeled those data based on the previous researches done in this area and adopt them for our motion algorithm. A precise velocity pattern and time-division have been described along different axes so that patient's biofeedback and postural stability in different walking phases can be recorded accordingly and motion-correction of the foot-boards can be done in consecutive cycles through iterative learning control algorithm with the help of motion sensors. PMID:19963951

Hasan, Muhammad Kamrul; Park, Jang-Ho; Park, Seung-Hun; Hwang, Sun-Hee; Khang, Gon

2009-01-01

110

Increasing weight-bearing physical activity and calcium-rich foods to promote bone mass gains among 9-11 year old girls: outcomes of the Cal-Girls study  

PubMed Central

Background A two-year, community-based, group-randomized trial to promote bone mass gains among 9–11 year-old girls through increased intake of calcium-rich foods and weight-bearing physical activity was evaluated. Methods Following baseline data collection, 30 5th-grade Girl Scout troops were randomized to a two-year behavioral intervention program or to a no-treatment control group. Evaluations were conducted at baseline, one year, and two years. Measures included bone mineral content, density, and area (measured by DXA), dietary calcium intake (24-hour recall), and weight-bearing physical activity (physical activity checklist interview). Mixed-model regression was used to evaluate treatment-related changes in bone mineral content (g) for the total body, lumbar spine (L1-L4), proximal femur, one-third distal radius, and femoral neck. Changes in eating and physical activity behavioral outcomes were examined. Results Although the intervention was implemented with high fidelity, no significant intervention effects were observed for total bone mineral content or any specific bone sites. Significant intervention effects were observed for increases in dietary calcium. No significant intervention effects were observed for increases in weight-bearing physical activity. Conclusion Future research needs to identify the optimal dosage of weight-bearing physical activity and calcium-rich dietary behavior change required to maximize bone mass gains in pre-adolescent and adolescent girls. PMID:16029507

French, Simone A; Story, Mary; Fulkerson, Jayne A; Himes, John H; Hannan, Peter; Neumark-Sztainer, Dianne; Ensrud, Kristine

2005-01-01

111

Gait Dynamics for Recognition and Classification  

E-print Network

This paper describes a representation of the dynamics of human walking action for the purpose of person identification and classification by gait appearance. Our gait representation is based on simple features such as ...

Lee, Lily

2001-09-01

112

Gait function in high-functioning autism and Asperger’s disorder  

Microsoft Academic Search

Gait abnormalities have been widely reported in individuals with autism and Asperger’s disorder. There is controversy as to\\u000a whether the cerebellum or the basal-ganglia frontostriatal regions underpin these abnormalities. This is the first direct\\u000a comparison of gait and upper-body postural features in autism and Asperger’s disorder. Clinical and control groups were matched\\u000a according to age, height, weight, performance, and full

Nicole J. Rinehart; Bruce J. Tonge; John L. Bradshaw; Robert Iansek; Peter G. Enticott; Jenny McGinley

2006-01-01

113

Bone peg fixation of a large chondral fragment in the weight-bearing portion of the lateral femoral condyle in an adolescent: a case report  

PubMed Central

Introduction Chondral fracture of the knee is relatively rare and the optimal treatment option for this injury is still controversial. In this report, we present the case of a patient with this injury who was treated surgically using the bone peg fixation procedure. There has been no literature reporting the use of this technique for fixation of a detached chondral fragment. Case presentation The patient was a 14-year-old Japanese boy who sustained a knee injury while kicking a soccer ball. Although routine radiographs showed no abnormality, magnetic resonance imaging showed a large full-thickness chondral defect in the weight-bearing portion of his lateral femoral condyle and a detached chondral fragment in the anterior region. The size of the defect (fragment) was 2cm by 1.5cm. At surgery, the chondral fragment was fixed with eight cortical bone pegs that were harvested from the anteromedial aspect of his tibia. Conclusions The postoperative magnetic resonance imaging at 4 months and the second-look arthroscopy at 12 months revealed apparent healing of the fragment. In the final follow-up examination at 26 months, a physical examination showed no swelling with recovery of full range of motion, and he could play soccer at the pre-injury level with no complaint. Based on the clinical course of this patient, it is thought that bone peg fixation can be a valuable option for fixation of a large chondral fracture of the knee. PMID:25248689

2014-01-01

114

Typical features of cerebellar ataxic gait  

Microsoft Academic Search

Background: Although gait disturbance is one of the most pronounced and disabling symptoms in cerebellar disease (CD), quantitative studies on this topic are rare.Objectives: To characterise the typical clinical features of cerebellar gait and to analyse ataxia quantitatively.Methods: Twelve patients with various cerebellar disorders were compared with 12 age matched controls. Gait was analysed on a motor driven treadmill using

H Stolze; S Klebe; G Petersen; J Raethjen; R Wenzelburger; K Witt; G Deuschl

2002-01-01

115

One leg swing through gait using two crutches. An analysis of the ground reaction forces and gait phases.  

PubMed

Using a Force Plate the gait cycle for one leg swing-through gait of ten normal subjects on Canadian crutches was monitored, and a composite diagram of forces on the lower limb and both crutches was produced. In addition the relationship of the stance and swing phase for both the lower limb and crutches was studied and the percentage of these phases and their overlap included on the composite diagram. The average maximum vertical ground reaction to the leg was 1.32 body weight, 16 per cent higher than that reported for normal walking. The horizontal force on the lower limb in the direction of walking was 0.35 body weight, compared to 0.15 for normal walking. Vertical ground reaction to crutches was on average 0.54 body weight on the side of the landing leg and 0.51 on the contralateral side. Horizontal ground reaction on the crutches at right angles to the direction of ambulation was 0.09 body weight on the right and 0.08 on the left. The results were considered to indicate caution in the prescription of one leg swing-through gait in subjects with diseased bone and joints in the lower limb. PMID:7376848

Stallard, J; Dounis, E; Major, R E; Rose, G K

1980-02-01

116

Polar Bears  

NSDL National Science Digital Library

Use the following websites to answer questions about the rapid disappearance of polar bears in the Arctic region. Polar Bear picture Polar Bear Tracker 1: What region in the world has the fewest polar bears? 2: Using the internet as a resource, provide some reasons as to why this region is suffering from the most polar bear differences? Polar Bears Change Diet 1: Why are polar bears having to change their diets? 2: List some other factors (besides diet) in the ...

Thomas, Mr.

2010-09-27

117

Pneumatic interactive gait rehabilitation orthosis: design and preliminary testing.  

PubMed

Motor rehabilitation techniques based on passive movement of the lower limbs have been developed over the past 15 years. Gait training automation is the latest innovation in these techniques. This paper describes the design and development of a pneumatic interactive gait rehabilitation orthosis (PIGRO), as well as the first experimental results obtained with healthy subjects. PIGRO consists of a modular and size-adaptable exoskeleton, pneumatic actuation systems for the six actuated degrees of freedom (DoF), and a control unit. The foot orthosis and ankle actuation can be removed and/or replaced with orthopaedic shoes so as to permit gait rehabilitation while advancing between parallel bars with ground contact and partial body weight support (i.e. not walking in place). Control logic provides closed-loop position control independently on each joint, with position feedback for each joint in real time. Imposed curves are physiological joint angles: it is also possible to choose between activating one or both legs and to modify curves to obtain different gait patterns if required. The paper concludes with a presentation of experimental results for the device's performance. PMID:21428150

Belforte, G; Eula, G; Appendino, S; Sirolli, S

2011-02-01

118

Altered Gait Termination Strategies Following a Concussion  

PubMed Central

The purpose was to determine if planned gait termination can identify acute and lingering motor control strategy alterations in post-concussion individuals. Controls completed 2 standard gait and 5 planned gait termination trials once while concussed individuals were tested on Day-1 and Day-10 post-concussion. Dependent variables included gait velocity and normalized, relative to standard gait, peak propulsive and braking forces. Control and only Day-1 post-concussion gait velocity differed. Normalized peak propulsive and braking forces were altered on both Day-1 and Day-10. Altered propulsive and braking forces persisted despite all concussion participants achieving their baseline values on standard concussion clinical tests. Thus gait termination can detect both acute and lingering motor control strategy alterations following concussion. PMID:23489951

Buckley, Thomas A.; Munkasy, Barry A.; Tapia-Lovler, Tiffen G.; Wikstrom, Erik A.

2013-01-01

119

Weight-Bearing MR Imaging as an Option in the Study of Gravitational Effects on the Vocal Tract of Untrained Subjects in Singing Phonation  

PubMed Central

Magnetic Resonance Imaging (MRI) of subjects in a supine position can be used to evaluate the configuration of the vocal tract during phonation. However, studies of speech phonation have shown that gravity can affect vocal tract shape and bias measurements. This is one of the reasons that MRI studies of singing phonation have used professionally trained singers as subjects, because they are generally considered to be less affected by the supine body position and environmental distractions. A study of untrained singers might not only contribute to the understanding of intuitive singing function and aid the evaluation of potential hazards for vocal health, but also provide insights into the effect of the supine position on singers in general. In the present study, an open configuration 0.25 T MRI system with a rotatable examination bed was used to study the effect of body position in 20 vocally untrained subjects. The subjects were asked to sing sustained tones in both supine and upright body positions on different pitches and in different register conditions. Morphometric measurements were taken from the acquired images of a sagittal slice depicting the vocal tract. The analysis concerning the vocal tract configuration in the two body positions revealed differences in 5 out of 10 measured articulatory parameters. In the upright position the jaw was less protruded, the uvula was elongated, the larynx more tilted and the tongue was positioned more to the front of the mouth than in the supine position. The findings presented are in agreement with several studies on gravitational effects in speech phonation, but contrast with the results of a previous study on professional singers of our group where only minor differences between upright and supine body posture were observed. The present study demonstrates that imaging of the vocal tract using weight-bearing MR imaging is a feasible tool for the study of sustained phonation in singing for vocally untrained subjects. PMID:25379885

Traser, Louisa; Burdumy, Michael; Richter, Bernhard; Vicari, Marco; Echternach, Matthias

2014-01-01

120

Polar Bear Polar Bear  

NSDL National Science Digital Library

In this lesson, students will listen for key details in a nonfiction text about polar bears. They will work at completing a graphic organizer with the teacher to help organize their thinking and understanding of key details about a text. They will also complete an independent assignment where they will draw or write two things that they learned about the topic.

Burgess, Kelly

2012-09-11

121

Gait Recognition Using Gait Entropy Image Khalid Bashir, Tao Xiang, Shaogang Gong  

E-print Network

condition and view angle, while others affect gait itself such as shoes, time and surface. De- spite to these limitations the current trend on gait representation seems to favour model free approaches. Model free

Gong, Shaogang

122

Characteristics of metal and ceramic total hip bearing surfaces and their effect on long-term ultra high molecular weight polyethylene wear.  

PubMed

The micromechanics of ultra high molecular weight polyethylene (UHMWPE) wear in total hip replacement are very complex. Polyethylene wear from the metal head and debris formation are two common types of wear. There are additional wear-related processes occurring at the metal-bearing surfaces that are not well-known, however. This study outlines these processes, including (1) surface wettability changes, (2) oxidative wear of metal surfaces, (3) microabrasion of metal surfaces from oxide film damage, and (4) surface abrasion from three-body polymethylmethacrylate and bone debris. These processes can contribute to metal ion release and a gradual increase in the roughness of the metal surfaces. This can lead to increased long-term UHMWPE wear. Of the metal alloys currently used in total hip replacements, Co-Cr-Mo alloy is significantly more resistant to roughening processes. Hard, stable, oxide: ceramic surfaces articulating against UHMWPE are essentially immune to these surface-roughening processes, however. In addition, they provide a more wettable surface, further minimizing polyethylene wear relative to metal surfaces. By analyzing metal release rates from metal-polyethylene wear tests, it is shown here that Co-Cr-Mo is gradually removed at a rate of about 0.1 micron per year (10(6) cycles), whereas 316L stainless steel is removed on the order of 0.2 microns per year and Ti-6Al-4V on the order of 1 micron per year. The wear rate of Co-Cr-Mo articulating against itself is reported to be still greater, at about 2-4 microns per year after an initial wear-in period. Because metal is gradually removed with articulation time, surface-hardening methods such as nitrogen ion implantation can be expected to provide only temporary resistance to these metal removal and surface-roughening processes. Hard, stable ceramic surfaces such as Al2O3 and ZrO2, however, can be expected to maintain their initial surface finish and thus minimize UHMWPE wear in the long term. PMID:8358943

Davidson, J A

1993-09-01

123

Cerebral Palsy Gait, Clinical Importance  

PubMed Central

ABSTRACT Cerebral palsy refers to a lesion on an immature brain, that determines permanent neurological disorders. Knowing the exact cause of the disease does not alter the treatment management. The etiology is 2-2.5/1000 births and the rate is constant in the last 40-50 years because advances in medical technologies have permitted the survival of smaller and premature new born children. Gait analysis has four directions: kinematics (represents body movements analysis without calculating the forces), kinetics (represents body moments and forces), energy consumption (measured by oximetry), and neuromuscular activity (measured by EMG). Gait analysis can observe specific deviations in a patient, allowing us to be more accurate in motor diagnoses and treatment solutions: surgery intervention, botulinum toxin injection, use of orthosis, physical kinetic therapy, oral medications, baclofen pump. PMID:24790675

TUGUI, Raluca Dana; ANTONESCU, Dinu

2013-01-01

124

Recent advances in functional neuroimaging of gait  

Microsoft Academic Search

Summary.  In this review, we discuss the contribution of functional neuroimaging to the understanding of the cerebral control of gait\\u000a in humans, both in healthy subjects and in patients with Parkinson’s disease. We illustrate different approaches that have\\u000a been used to address this issue, ranging from the imaging of actual gait performance to the study of initiation and imagery\\u000a of gait.

M. Bakker; C. C. P. Verstappen; B. R. Bloem; I. Toni

2007-01-01

125

NAVIGATION AND GAIT PLANNING FOR PLANAR WALKER  

Microsoft Academic Search

Locomotion and navigation of a surface walking\\/climbing robot - Planar Walker, based on a novel planar 8-bar mechanism are investigated. The robot moves on a surface through decoupled transverse gaits and turning gaits with finite lengths and finite rotation angles. Motions of the gaits are modeled using planar rigid motion group SE(2). Three point-to-point navigation methods are developed for various

I-Ming Chen; Song Huat Yeo; R. S. Senanayake

126

Hölder exponent spectra for human gait  

NASA Astrophysics Data System (ADS)

The stride interval time series in normal human gait is not strictly constant, but fluctuates from step to step in a complex manner. More precisely, it has been shown that the control process for human gait is a fractal random phenomenon, that is, one with a long-term memory. Herein we study the Hölder exponent spectra for the slow, normal and fast gaits of 10 young healthy men in both free and metronomically triggered conditions and establish that the stride interval time series is more complex than a monofractal phenomenon. A slightly multifractal and non-stationary time series under the three different gait conditions emerges.

Scafetta, N.; Griffin, L.; West, B. J.

2003-10-01

127

Optics in gait analysis and anthropometry  

NASA Astrophysics Data System (ADS)

Since antiquity, human gait has been studied to understand human movement, the kind of gait, in some cases, can cause musculoskeletal disorders or other health problems; in addition, also from antiquity, anthropometry has been important for the design of human items such as workspaces, tools, garments, among others. Nowadays, thanks to the development of optics and electronics, more accurate studies of gait and anthropometry can be developed. This work will describe the most important parameters for gait analysis, anthropometry and the optical systems used.

Silva Moreno, Alejandra Alicia

2013-11-01

128

Single-trial classification of gait and point movement preparation from human EEG.  

PubMed

Neuroimaging studies provide evidence of cortical involvement immediately before and during gait and during gait-related behaviors such as stepping in place or motor imagery of gait. Here we attempt to perform single-trial classification of gait intent from another movement plan (point intent) or from standing in place. Subjects walked naturally from a starting position to a designated ending position, pointed at a designated position from the starting position, or remained standing at the starting position. The 700 ms of recorded electroencephalography (EEG) before movement onset was used for single-trial classification of trials based on action type and direction (left walk, forward walk, right walk, left point, right point, and stand) as well as action type regardless of direction (stand, walk, point). Classification using regularized LDA was performed on a principal components analysis (PCA) reduced feature space composed of coefficients from levels 1 to 9 of a discrete wavelet decomposition using the Daubechies 4 wavelet. We achieved significant classification for all conditions, with errors as low as 17% when averaged across nine subjects. LDA and PCA highly weighted frequency ranges that included movement related potentials (MRPs), with smaller contributions from frequency ranges that included mu and beta idle motor rhythms. Additionally, error patterns suggested a spatial structure to the EEG signal. Future applications of the cortical gait intent signal may include an additional dimension of control for prosthetics, preemptive corrective feedback for gait disturbances, or human computer interfaces (HCI). PMID:23781166

Velu, Priya D; de Sa, Virginia R

2013-01-01

129

Ankle arthrodesis. Long-term follow-up with gait analysis.  

PubMed

A functional assessment of twelve patients after ankle arthrodesis for post-traumatic arthritis was carried out by means of an extensive clinical evaluation and gait analysis after an average follow-up of eight years. A weighted point system was developed to grade ankle function clinically. The data on gait analysis were examined to determine the effect of arthrodesis of the ankle on the over-all pattern of walking. Under conditions of normal daily living while wearing shoes, all patients functioned well after arthrodesis. The gait-analysis data obtained with the patients wearing shoes showed excellent gait characteristics, and the ankle motion that had been lost was compensated for by: (1) motion of the small joints of the ipsilateral foot; (2) altered motion of the ankle in the contralateral limb; and (3) appropriate footwear. While the patients were walking barefooted, some adverse effects of fusion of the ankle were evident. Velocity of gait was slowed and the length of stride was shortened in all twelve patients. One patient whose ankle had been fused in an equinus position had a back-knee deformity during stance phase, and another walked only on his toes when he was without shoes. The gait patterns of all patients were markedly improved when they were wearing shoes with appropriate heel heights. PMID:489661

Mazur, J M; Schwartz, E; Simon, S R

1979-10-01

130

A gait index may underestimate changes of gait: a comparison of the Movement Deviation Profile and the Gait Deviation Index.  

PubMed

The ability of the Movement Deviation Profile (MDP) and Gait Deviation Index (GDI) to detect gait changes was compared in a child with cerebral palsy who underwent game training. Conventional gait analysis showed that sagittal plane angles became mirrored about normality after training. Despite considerable gait changes, the GDI showed minimal change, while the MDP detected a difference equal to a shift between 10-9 on the Functional Assessment Questionnaire scale. Responses of the GDI and MDP were examined during a synthetic transition of the patient's curves from before intervention to a state mirrored about normality. The GDI showed a symmetric response on the two opposite sides of normality but the neural network based MDP gave an asymmetric response reflecting faithfully the unequal biomechanical consequences of joint angle changes. In conclusion, the MDP can detect altered gait even if the changes are missed by the GDI. PMID:23521124

Barton, Gabor J; Hawken, Malcolm B; Holmes, Gill; Schwartz, Michael H

2015-01-01

131

Optimum energy loss in electro magnetic bearing  

Microsoft Academic Search

This paper includes weight optimization method of rotor and analysis of total power loss in radial magnetic bearing consisting of four, eight and twelve poles. Weight optimization reduces copper loss in bearing since the electromagnetic force is reduced due to optimized rotor. Further numbers of poles in magnetic bearing are varied for same electromagnetic force 350 N and stator is

Santosh Shelke; R. V. Chalam

2011-01-01

132

Variability and similarity of gait as evaluated by joint angles: implications for forensic gait analysis.  

PubMed

Closed-circuit television (CCTV) footage is used in criminal investigations to compare perpetrators with suspects. Usually, incomplete gait cycles are collected, making evidential gait analysis challenging. This study aimed to analyze the discriminatory power of joint angles throughout a gait cycle. Six sets from 12 men were collected. For each man, a variability range VR (mean ± 1SD) of a specific joint angle at a specific time point (a gait cycle was 100 time points) was calculated. In turn, each individual was compared with the 11 others, and whenever 1 of these 11 had a value within this individual’s VR, it counted as positive. By adding the positives throughout the gait cycle, we created simple bar graphs; tall bars indicated a small discriminatory power, short bars indicated a larger one. The highest discriminatory power was at time points 60–80 in the gait cycle. We show how our data can assess gait data from an actual case. PMID:24745080

Yang, Sylvia X M; Larsen, Peter K; Alkjær, Tine; Simonsen, Erik B; Lynnerup, Niels

2014-03-01

133

Motor imagery of gait: a quantitative approach  

Microsoft Academic Search

Motor imagery (MI) is widely used to study cognitive aspects of the neural control of action. Prior studies were mostly centred on hand and arm move- ments. Recently a few studies have used imagery tasks to explore the neurophysiology of human gait, but it remains unclear how to ascertain whether subjects actually perform imagery of gait as requested. Here we

M. Bakker; F. P. de Lange; J. A. Stevens; I. Toni; B. R. Bloem

2006-01-01

134

Gait patterns in children with autism  

Microsoft Academic Search

BackgroundVery few studies have examined the gait patterns of children with autism. A greater awareness of movement deviations could be beneficial for treatment planning. The purpose of this study was to compare kinematic and kinetic gait patterns in children with autism versus age-matched controls.

Matthew Calhoun; Margaret Longworth; Victoria L. Chester

2011-01-01

135

Quadruped Gait Learning Using Cyclic Genetic Algorithms  

E-print Network

and in particular, Genetic Algorithms, have previously been used to develop gaits for legged (primarily hexapod]. In a previous work Parker made use of cyclic genetic algorithms to develop walking gaits for a hexapod robot [5]. Each of the six legs of this hexapod robot could only move vertically and horizontally and the number

Parker, Gary B.

136

Average Gait Differential Image Based Human Recognition  

PubMed Central

The difference between adjacent frames of human walking contains useful information for human gait identification. Based on the previous idea a silhouettes difference based human gait recognition method named as average gait differential image (AGDI) is proposed in this paper. The AGDI is generated by the accumulation of the silhouettes difference between adjacent frames. The advantage of this method lies in that as a feature image it can preserve both the kinetic and static information of walking. Comparing to gait energy image (GEI), AGDI is more fit to representation the variation of silhouettes during walking. Two-dimensional principal component analysis (2DPCA) is used to extract features from the AGDI. Experiments on CASIA dataset show that AGDI has better identification and verification performance than GEI. Comparing to PCA, 2DPCA is a more efficient and less memory storage consumption feature extraction method in gait based recognition. PMID:24895648

Chen, Jinyan; Liu, Jiansheng

2014-01-01

137

Polar Bear  

NSDL National Science Digital Library

This site from the World Wildlife Fund (WWF) International provides general information about polar bears as well as data on the movements of two radio-collared bears, along with the ice status, through a series of online maps.

2007-01-01

138

Pathology Case Study: Gait Disorders  

NSDL National Science Digital Library

This is a case study presented by the University of Pittsburgh Department of Pathology, which describes a 62-year-old woman with a 20-year history of gait disorders and dizziness. Visitors are given patient history, laboratory findings, along with microscopic descriptions, including images, and are given the opportunity to diagnose the patient. A "Final Diagnosis" section provides a discussion of the findings as well as references. This is an excellent resource for students in the health sciences to familiarize themselves with using patient history and laboratory results to diagnose disease. It is also a helpful site for educators to use to introduce or test student learning in neuropathology.

2009-04-21

139

Characterization of gait pattern by 3D angular accelerations in hemiparetic and healthy gait.  

PubMed

Characterization of gait pattern is of interest for clinical gait assessment. Past developments of ambulatory measurement systems have still limitations for daily usage in the clinical environment. This study investigated the potential of 3D angular accelerations of foot, shank, and thigh to characterize gait events and phases of ten healthy and ten hemiparetic subjects. The key feature of the system was the use of angular accelerations obtained by differential measurement. Further, the effect of sensor position and walking cadence on the signal was investigated. We found that gait phases are characterized as modulated amplitudes of angular accelerations of foot, shank, and thigh. Increasing the gait cadence from 70 steps/min to 100 steps/min caused an amplitude increase of the magnitude of the vector, summing all 3D angular accelerations on the sensor position (p<0.001). Comparison of healthy and hemiparetic gait showed a lower mean of the magnitude of the vector during the loading response in the hemiparetic gait (p<0.05), while during pre-swing and swing no significant differences between healthy and hemiparetic gait were observed. A comparison of the tangential acceleration component in the frontal plane showed no statistically significant difference between healthy and hemiparetic gait. Further, no statistically significant difference between the tangential components was found for both groups. This method demonstrated promising results for a possible use for gait assessment. PMID:22840891

Rueterbories, Jan; Spaich, Erika G; Andersen, Ole K

2013-02-01

140

Person identification based on gait using dynamic body parameters  

Microsoft Academic Search

Gait as a behavioural biometrics has been the subject of recent investigations. One of the unique advantages of human gait is that it can be perceived from a distance. A varied range of research has been undertaken within the field of gait recognition. A gait describes the manner of a person's walking. It can be acquired at a distance and

Jasvinder Pal Singh; Sanjeev Jain

2010-01-01

141

The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements  

PubMed Central

Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods. PMID:22904606

Kurtz, Steven M.; Toth, Jeffrey M.; Siskey, Ryan; Ciccarelli, Lauren; MacDonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, André

2012-01-01

142

The Latest Lessons Learned from Retrieval Analyses of Ultra-High Molecular Weight Polyethylene, Metal-on-Metal, and Alternative Bearing Total Disc Replacements.  

PubMed

Knowledge regarding the in vivo performance and periposthetic tissue response of cervical and lumbar total disc replacements (TDRs) continues to expand. This review addresses the following four main questions: 1) What are the latest lessons learned from polyethylene in large joints and how are they relevant to current TDRs? 2) What are the latest lessons learned regarding adverse local tissue reactions from metal-on-metal, CoCr bearings in large joints and how are they relevant to current TDRs? 3) What advancements have been made in understanding the in vivo performance of alternative biomaterials, such as stainless steel and polycarbonate urethane, for TDRs in the past five years? 4) How has retrieval analysis of all these various artificial disc bearing technologies advanced the state of the art in preclinical testing of TDRs? The study of explanted artificial discs and their associated tissues can help inform bearing selection as well as the design of future generations of disc arthroplasty. Analyzing retrieved artificial discs is also essential for validating preclinical test methods. PMID:22904606

Kurtz, Steven M; Toth, Jeffrey M; Siskey, Ryan; Ciccarelli, Lauren; Macdonald, Dan; Isaza, Jorge; Lanman, Todd; Punt, Ilona; Steinbeck, Marla; Goffin, Jan; van Ooij, André

2012-03-01

143

Gait characteristics of the elderly.  

PubMed

The purpose of this study was to investigate the effects of aging on gait for people 60 years old and above using gait variables commonly applied in sport shoe analysis. Thirty-eight subjects were divided into age groups: 60-69 years and 70-82 years. They walked along a carpeted walkway at a comfortable walking speed wearing a pair of their own walking shoes and a pair of laboratory supplied sports shoes. Kinetic and kinematic data were collected and subsequently analysed. Subjects of the older age group (70-82 years) displayed less movement in the subtalar joint during the support phase of walking with the personal shoes than subjects of the younger age group. Subjects of the older age group walked more slowly and exerted lower anterior-posterior forces with both the personal and laboratory shoes than subjects of the younger age group. Trends suggest (not statistically significant) that foot movement during mid-stance decreases with increasing age. It is speculated that this decrease in foot movement may be due to increased stiffness in the ankle and subtalar joint with age and/or due to a selection process of the older test subjects to prefer shoes with more support. Further research is needed to support or reject these speculations. PMID:23915838

Nigg, B M; Skleryk, B N

1988-05-01

144

[Hearing loss and gait ataxia without dizziness. Hemosiderosis].  

PubMed

Superficial cerebral hemosiderosis is characterized by sensorineural hearing loss, gait ataxia and pyramidal signs with irreversible myelopathy. It is caused by chronic hemorrhage into the subarachnoid space with hemosiderin deposition in the subpial, leptomeningeal and subependymal layers. Imaging of the entire neuroaxis is indicated to localize a source of bleeding, including cerebral and spinal angiography when necessary. Taking into account clinical signs and symptoms the interpretation of T2*-weighted images allows the radiologist to set the course for the optimal therapeutic regimen. PMID:19787328

Albrecht, L; Gabriel, S; Packebusch, A; Roth, M; Beine, K H; Faltraco, F

2009-12-01

145

Gait instability and fractal dynamics of older adults with a “cautious” gait: why do certain older adults walk fearfully?  

Microsoft Academic Search

Many older adults walk with a cautious and impaired gait of unknown origin, however, the relationship between fear of falling and the observed gait changes is not well understood. To better understand the “cautious” gait of the elderly, we tested the hypothesis that temporal gait variability, putatively a marker of intrinsic walking unsteadiness, is increased among older adults with a

T. Herman; N. Giladi; T. Gurevich; J. M. Hausdorff

2005-01-01

146

Gait variability and disability in multiple sclerosis.  

PubMed

Gait variability is clinically relevant in some populations, but there is limited documentation of gait variability in persons with multiple sclerosis (MS). This investigation examined average and variability of spatiotemporal gait parameters in persons with MS and healthy controls and subsequent associations with disability status. 88 individuals with MS (age 52.4±11.1) and 20 healthy controls (age 50.9±8.7) performed two self-paced walking trials on a 7.9-m electronic walkway to determine gait parameters. Disability was indexed by the Expanded Disability Status Scale (EDSS) and ranged between 2.5 and 6.5. Gait variability was indexed by standard deviation (SD) and coefficient of variation (CV=SD/mean) of step time, step length, and step width. Average gait parameters were significantly correlated with EDSS (?=0.756-0.609) and were significantly different in individuals with MS compared to controls (p?0.002). Also, step length (p<0.001) and step time (p<0.001) variability were both significantly greater in MS compared to controls. EDSS was positively correlated with step length variability and individuals with MS who used assistive devices to walk had significantly greater step length variability than those who walked independently (p's<.05). EDSS was correlated with step time and length variability even when age was taken into account. Additionally, Fisher's z test of partial correlations revealed that average gait parameters were more closely related to disability status than gait variability in individuals with MS. This suggests that focusing on average gait parameters may be more important than variability in therapeutic interventions in MS. PMID:23153835

Socie, Michael J; Motl, Robert W; Pula, John H; Sandroff, Brian M; Sosnoff, Jacob J

2013-05-01

147

Prevention of Cartilage Degeneration and Gait Asymmetry by Lubricin Tribosupplementation in the Rat Following ACL Transection  

PubMed Central

Objective To investigate whether cartilage degeneration is prevented or minimized in an anterior cruciate ligament (ACL) injury rat model following a single dose-escalated intra-articular injection of lubricin derived from human synoviocytes in culture (HSL). Methods Unilateral ACL transection (ACLT) of the right hindlimb was performed in Lewis rats (N = 56). Control animals underwent a capsulotomy alone leaving the ACL intact (N = 11). Intra-articular injections (50?l/injection) of PBS (N = 14) and HSL (N = 14; 1600?g/ml) were performed on day 7 post-surgery. Animals were euthanized on day 70 post-surgery. Histological specimens were immunoprobed for lubricin, and sulfated glycosaminoglycans. Urinary CTX-II (uCTX-II) levels were measured on day 35 and 70 post-surgery. Hindlimb maximum applied force was determined using a variable resistor walkway to monitor quadruped gait asymmetries. Results Increased immunostaining for lubricin in the superficial zone and on the surface of cartilage was observed in lubricin-treated and control animals but not the PBS-treated nor the untreated ACLT animals. On post-operative day 35 and 70, uCTXII levels of HSL-treated animals were lower than corresponding untreated and PBS-treated (p=0.005; p<0.001 respectively) animals. ACLT animals treated with HSL and control animals distributed their weight equally between hindlimbs compared to PBS treated or untreated animals (p<0.01). Conclusion A single intra-articular injection of concentrated lubricin, following ACLT, reduced collagen type II degradation and improved weight bearing in the affected joint. This study supports the practice of tribosupplementation with lubricin in retarding cartilage degeneration and possibly the development of post-traumatic OA. PMID:22127873

Jay, Gregory D.; Elsaid, Khaled A.; Kelly, Karen A.; Anderson, Scott C.; Zhang, Ling; Teeple, Erin; Waller, Kimberly; Fleming, Braden C.

2011-01-01

148

Engine bearings  

SciTech Connect

This patent describes a hydrodynamic journal bearing combination comprising: a rotary journal shaft having a circular cross section; a journal bearing surrounding the rotary journal shaft. The journal bearing has at least two symmetrical arcuate bearing surfaces, each arcuate surface having the same radius. The radius is slightly greater than that of the rotary journal shaft. Each arcuate bearing surface defines less than 180/sup 0/ and has a mid point intermediate it ends. The arcuate bearing surfaces are disposed with their mid points diametrically opposed. The journal shaft is positioned within the area covered by the two arcuate surfaces whereby a small clearance is maintained therebetween at all points under both load and no-load lubricant filling the aforesaid clearance between the journal shaft and the two arcuate surfaces.

Showalter, M.R.

1987-05-26

149

Controlling patient participation during robot-assisted gait training  

PubMed Central

Background The overall goal of this paper was to investigate approaches to controlling active participation in stroke patients during robot-assisted gait therapy. Although active physical participation during gait rehabilitation after stroke was shown to improve therapy outcome, some patients can behave passively during rehabilitation, not maximally benefiting from the gait training. Up to now, there has not been an effective method for forcing patient activity to the desired level that would most benefit stroke patients with a broad variety of cognitive and biomechanical impairments. Methods Patient activity was quantified in two ways: by heart rate (HR), a physiological parameter that reflected physical effort during body weight supported treadmill training, and by a weighted sum of the interaction torques (WIT) between robot and patient, recorded from hip and knee joints of both legs. We recorded data in three experiments, each with five stroke patients, and controlled HR and WIT to a desired temporal profile. Depending on the patient's cognitive capabilities, two different approaches were taken: either by allowing voluntary patient effort via visual instructions or by forcing the patient to vary physical effort by adapting the treadmill speed. Results We successfully controlled patient activity quantified by WIT and by HR to a desired level. The setup was thereby individually adaptable to the specific cognitive and biomechanical needs of each patient. Conclusion Based on the three successful approaches to controlling patient participation, we propose a metric which enables clinicians to select the best strategy for each patient, according to the patient's physical and cognitive capabilities. Our framework will enable therapists to challenge the patient to more activity by automatically controlling the patient effort to a desired level. We expect that the increase in activity will lead to improved rehabilitation outcome. PMID:21429200

2011-01-01

150

Design of a robot for gait rehabilitation  

E-print Network

The ability to walk is important for independent living and when this capacity is affected by injury, gait therapy is the traditional approach to re-train the nervous system, to re-build muscle strength, to improve balance, ...

Bosecker, Caitlyn Joyce

2009-01-01

151

Investigation of first ray mobility during gait by kinematic fluoroscopic imaging-a novel method  

PubMed Central

Background It is often suggested that sagittal instability at the first tarso-metatarsal joint level is a primary factor for hallux valgus and that sagittal instability increases with the progression of the deformity. The assessment of the degree of vertical instability is usually made by clinical evaluation while any measurements mostly refer to a static assessment of medial ray mobility (i.e. the plantar/dorsal flexion in the sagittal plane). Testing methods currently available cannot attribute the degree of mobility to the corresponding anatomical joints making up the medial column of the foot. The aim of this study was to develop a technique which allows for a quantification of the in-vivo sagittal mobility of the joints of the medial foot column during the roll-over process under full weight bearing. Methods Mobility of first ray bones was investigated by dynamic distortion-free fluoroscopy (25 frames/s) of 14 healthy volunteers and 8 patients with manifested clinical instability of the first ray. A CAD-based evaluation method allowed the determination of mobility and relative displacements and rotations of the first ray bones within the sagittal plane during the stance phase of gait. Results Total flexion of the first ray was found to be 13.63 (SD 6.14) mm with the healthy volunteers and 13.06 (SD 8.01) mm with the patients (resolution: 0.245 mm/pixel). The dorsiflexion angle was 5.27 (SD 2.34) degrees in the healthy volunteers and increased to 5.56 (SD 3.37) degrees in the patients. Maximum rotations were found at the naviculo-cuneiform joints and least at the first tarso-metatarsal joint level in both groups. Conclusions Dynamic fluoroscopic assessment has been shown to be a valuable tool for characterisation of the kinematics of the joints of the medial foot column during gait. A significant difference in first ray flexion and angular rotation between the patients and healthy volunteers however could not be found. PMID:22316084

2012-01-01

152

Toward understanding the limits of gait recognition  

NASA Astrophysics Data System (ADS)

Most state of the art video-based gait recognition algorithms start from binary silhouettes. These silhouettes, defined as foreground regions, are usually detected by background subtraction methods, which results in holes or missed parts due to similarity of foreground and background color, and boundary errors due to video compression artifacts. Errors in low-level representation make it hard to understand the effect of certain conditions, such as surface and time, on gait recognition. In this paper, we present a part-level, manual silhouette database consisting of 71 subjects, over one gait cycle, with differences in surface, shoe-type, carrying condition, and time. We have a total of about 11,000 manual silhouette frames. The purpose of this manual silhouette database is twofold. First, this is a resource that we make available at http://www.GaitChallenge.org for use by the gait community to test and design better silhouette detection algorithms. These silhouettes can also be used to learn gait dynamics. Second, using the baseline gait recognition algorithm, which was specified along with the HumanID Gait Challenge problem, we show that performance from manual silhouettes is similar and only sometimes better than that from automated silhouettes detected by statistical background subtraction. Low performances when comparing sequences with differences in walking surfaces and time-variation are not fully explained by silhouette quality. We also study the recognition power in each body part and show that recognition based on just the legs is equal to that from the whole silhouette. There is also significant recognition power in the head and torso shape.

Liu, Zongyi; Malave, Laura; Osuntogun, Adebola; Sudhakar, Preksha; Sarkar, Sudeep

2004-08-01

153

The Cow Gait Recognition Using CHLAC  

Microsoft Academic Search

This paper reports the preliminary experiments on the cow identification via gait recognition of motion images. The eight cows walking under two different situations have been precisely identified by Cubic Higher-order Lo- cal Auto-Correlation (CHLAC). The cow gait recognition using CHLAC is expected to be a landmark achievement for realizing cost-effective dairy cattle breeding management systems which do not use

Shu Mimura; Keichi Itoh; Takumi Kobayashi; Tomohiro Takigawa; Atsushi Tajima; Atsushi Sawamura; Nobuyuki Otsu

2008-01-01

154

The chronic effects of concussion on gait  

Microsoft Academic Search

BackgroundConcussion has a clear effect on motor control with acute alterations in gait documented up to 30 days post injury. These changes include increased stance time and decreased velocity. It is unknown if alterations persist beyond one month post-injury.ObjectiveTo evaluate the chronic effects of concussion on gait in individuals with and without an injury history.DesignA cross-sectional study.SettingA laboratory setting.Participants68 individuals

D Martini; M Sabin; S Depesa; E Leal; T Negrete; J Sosnoff; S Broglio

2011-01-01

155

Influence of backpack load and gait speed on plantar forces during walking.  

PubMed

The purpose of this study is to examine the differences in plantar force associated with changes in backpack load and gait speed during walking. The F-scan tethered system was used to collect plantar pressure data. Subjects were asked to walk on a treadmill with varied levels of backpack load (0%, 10%, 20%, and 30% of body mass) and gait speed (4, 5, and 6 km/h). We found that an increase in gait speed and backpack load lead to increase in the magnitude of the first vertical ground reaction force (vGRF) peak. Greater magnitudes of the second vGRF peak were only associated with an increase when gait speeds were 4 km/h and 5 km/h. There was no speed-related change in the magnitudes of the second vGRF peak at the speed of 6 km/h. The results of this study may be important for the purpose of constituting a load-bearing walking program for protecting against osteoporosis. PMID:24067124

Watanabe, Kazuhiko; Wang, Yun

2013-01-01

156

Polar Bear  

USGS Publications Warehouse

Polar bears are long-lived, late-maturing carnivores that have relatively low rates of reproduction and natural mortality. Their populations are susceptible to disturbance from human activities, such as the exploration and development of mineral resources or hunting. Polar bear populations have been an important renewable resource available to coastal communities throughout the Arctic for thousands of years.

Amstrup, S.D.

1988-01-01

157

Symmetrical gaits of Cebus apella: implications for the functional significance of diagonal sequence gait in primates  

Microsoft Academic Search

Quadrupedal locomotion of primates is distinguished from the quadrupedalism of many other mammals by several features, including a diagonal sequence (DS) footfall used in symmetrical gaits. This presumably unique feature of primate locomotion has been attributed to an ancestral adaptation for cautious arboreal quadrupedalism on thin, flexible branches. However, the functional significance of DS gait remains largely hypothetical. The study

Ian J. Wallace; Brigitte Demes

2008-01-01

158

Fixed or mobile-bearing total knee arthroplasty  

PubMed Central

Fixed and mobile-bearing in total knee arthroplasty are still discussed controversially. In this article, biomechanical and clinical aspects in both fixed and mobile-bearing designs were reviewed. In biomechanical aspect, the mobile-bearing design has proved to provide less tibiofemoral contact stresses under tibiofemoral malalignment conditions. It also provides less wear rate in in-vitro simulator test. Patients with posterior stabilized mobile-bearing knees had more axial tibiofemoral rotation than patients with posterior stabilized fixed-bearing knees during gait as well as in a deep knee-bend activity. However, in clinical aspect, the mid-term or long-term survivorship of mobile-bearing knees has no superiority over that of fixed-bearing knees. The theoretical advantages for mobile-bearing design to provide a long-term durability have not been demonstrated by any outcome studies. Finally, the fixed-bearing design with all-polyethylene tibial component is suggested for relatively inactive, elder people. The mobile-bearing design is suggested for younger or higher-demand patients due to the potential for reduced polyethylene wear and more normal kinematics response after joint replacement. For younger surgeon, the fixed-bearing design is suggested due to less demand for surgical technique. For experienced surgeon, one familiar surgical protocol and instrumentation is suggested rather than implant design, either fixed-bearing or mobile-bearing. PMID:17204165

Huang, Chun-Hsiung; Liau, Jiann-Jong; Cheng, Cheng-Kung

2007-01-01

159

Hydrodynamic squeeze-film bearings for gyroscopes  

NASA Technical Reports Server (NTRS)

Experimental tests are conducted on squeeze-film bearings by applying electricity to piezoelectric ceramics, causing vibrations at thousands or millions of Hz that are amplified and transmitted to the bearing. Rotor operation through 24,000 rpm without whirl instability proved bearing ability to support rotor weight without hydrodynamic action.

Chiang, T.; Smith, R. L.

1970-01-01

160

49 CFR 229.69 - Side bearings.  

Code of Federal Regulations, 2010 CFR

... Suspension System § 229.69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not...than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in contact unless designed to...

2010-10-01

161

49 CFR 229.69 - Side bearings.  

Code of Federal Regulations, 2012 CFR

... Suspension System § 229.69 Side bearings. (a) Friction side bearings with springs designed to carry weight may not...than 25 percent of the springs in any one nest broken. (b) Friction side bearings may not be run in contact unless designed to...

2012-10-01

162

Encapsulated HTS bearings: technical and cost considerations  

Microsoft Academic Search

Thermal encapsulation of HTS is one way to fabricate high-efficient HTS magnetic bearings for flywheels, motors and generators. We have been designed, manufactured and tested 200 mm axial and radial bearings for loads close to 300 kg. The maximum load to bearing weight is in the 10 to 1 ratio. At 77 K, a vacuum cryostat around the HTS reduces

F. N. Werfel; U. Floegel-Delor; T. Riedel; R. Rothfeld; D. Wippich; B. Goebel

2005-01-01

163

White Matter Hyperintensities, Exercise and Improvement in Gait Speed: Does the Type of Gait Rehabilitation Matter?  

PubMed Central

Background and Objectives White matter hyperintensities (WMH) on brain MRI are associated with cognitive and mobility impairment in older adults. We examined whether WMH in tracts in older adults with mobility impairment are linked to outcomes of gait rehabilitation interventions. Design A 12-week randomized controlled single-blind trial. Setting University-based mobility research laboratory. Participants Ambulatory adults aged 65 and older with mobility impairment. Intervention A conventional gait intervention focusing on walking, endurance, balance, and strength (WEBS, n=21) compared to a task-oriented intervention focused on timing and coordination of gait (TC, n=23). Measurements We measured self-paced gait speed over an instrumented walkway, pre and post intervention, and quantified WMH and brain volumes on pre-intervention brain MRI using an automated segmentation process. We overlaid a white matter tract atlas on the segmented images to measure tract WMH volumes and normalized WMH volumes to total brain volume. Aggregate WMH volumes in all white matter tracts and individual WMH volumes in specific longitudinal tracts (the superior longitudinal fasciculus, inferior longitudinal fasciculus and the fronto-occipital fasciculus) and cingulum were obtained. Results Gait speed gains in the TC group were of the same magnitude, independent of the WMH volume measures in all except the cingulum. However, in the WEBS group, gain in gait speed was smaller with greater overall tract WMH volumes (P<0.001) and with greater WMH volume in the three longitudinal tracts (P< 0.001 to 0.025). Conclusion Gains in gait speed with two types of gait rehabilitation are associated with individual differences in WMH. Task-oriented therapy that targets timing and coordination of gait may particularly benefit older adults with WMH in brain tracts that influence gait and cognition. PMID:23590257

Nadkarni, Neelesh K.; Studenski, Stephanie A.; Perera, Subashan; Rosano, Caterina; Aizenstein, Howard J.; Brach, Jennifer S.; VanSwearingen, Jessie M.

2013-01-01

164

Effect of backpack load on the head, cervical spine and shoulder postures in children during gait termination.  

PubMed

Twelve boys with an average age of 9.9 years were instructed to carry backpacks that weighed 0%, 10% and 15% of their body weights (BWs) to complete planned and unplanned gait termination experiments. The craniohorizontal, craniovertebral and sagittal shoulder posture angles at the sagittal plane as well as the anterior head alignment and coronal shoulder posture angles at the coronal plane were analysed. Results revealed significantly smaller craniohorizontal and sagittal shoulder posture angles during planned gait termination and a significantly smaller sagittal shoulder posture angle during unplanned gait termination under loaded conditions compared with those at 0% BW backpacks. Furthermore, the coronal shoulder posture angles at 10% and 15% BW during planned and unplanned gait terminations were significantly larger than those at 0% BW. Therefore, subjects were more likely to have a forward head posture, rounded shoulder posture and increased lateral tilting of the shoulders during gait termination as backpack loads were increased. However, gait termination, whether planned or unplanned, did not elicit a remarkable effect on posture. PMID:24206277

Mo, Shi Wei; Xu, Dong-Qing; Li, Jing Xian; Liu, Meng

2013-01-01

165

Gait Initiation in Children with Rett Syndrome  

PubMed Central

Rett syndrome is an X-linked neurodevelopmental condition mainly characterized by loss of spoken language and a regression of purposeful hand use, with the development of distinctive hand stereotypies, and gait abnormalities. Gait initiation is the transition from quiet stance to steady-state condition of walking. The associated motor program seems to be centrally mediated and includes preparatory adjustments prior to any apparent voluntary movement of the lower limbs. Anticipatory postural adjustments contribute to postural stability and to create the propulsive forces necessary to reach steady-state gait at a predefined velocity and may be indicative of the effectiveness of the feedforward control of gait. In this study, we examined anticipatory postural adjustments associated with gait initiation in eleven girls with Rett syndrome and ten healthy subjects. Muscle activity (tibialis anterior and soleus muscles), ground reaction forces and body kinematic were recorded. Children with Rett syndrome showed a distinctive impairment in temporal organization of all phases of the anticipatory postural adjustments. The lack of appropriate temporal scaling resulted in a diminished impulse to move forward, documented by an impairment in several parameters describing the efficiency of gait start: length and velocity of the first step, magnitude and orientation of centre of pressure-centre of mass vector at the instant of (swing-)toe off. These findings were related to an abnormal muscular activation pattern mainly characterized by a disruption of the synergistic activity of antagonistic pairs of postural muscles. This study showed that girls with Rett syndrome lack accurate tuning of feedforward control of gait. PMID:24743294

Isaias, Ioannis Ugo; Dipaola, Mariangela; Michi, Marlies; Marzegan, Alberto; Volkmann, Jens; Rodocanachi Roidi, Marina L.; Frigo, Carlo Albino; Cavallari, Paolo

2014-01-01

166

Gait synchronization in Caenorhabditis elegans.  

PubMed

Collective motion is observed in swarms of swimmers of various sizes, ranging from self-propelled nanoparticles to fish. The mechanisms that govern interactions among individuals are debated, and vary from one species to another. Although the interactions among relatively large animals, such as fish, are controlled by their nervous systems, the interactions among microorganisms, which lack nervous systems, are controlled through physical and chemical pathways. Little is known, however, regarding the mechanism of collective movements in microscopic organisms with nervous systems. To attempt to remedy this, we studied collective swimming behavior in the nematode Caenorhabditis elegans, a microorganism with a compact nervous system. We evaluated the contributions of hydrodynamic forces, contact forces, and mechanosensory input to the interactions among individuals. We devised an experiment to examine pair interactions as a function of the distance between the animals and observed that gait synchronization occurred only when the animals were in close proximity, independent of genes required for mechanosensation. Our measurements and simulations indicate that steric hindrance is the dominant factor responsible for motion synchronization in C. elegans, and that hydrodynamic interactions and genotype do not play a significant role. We infer that a similar mechanism may apply to other microscopic swimming organisms and self-propelled particles. PMID:24778261

Yuan, Jinzhou; Raizen, David M; Bau, Haim H

2014-05-13

167

Advancing clinical gait analysis through technology and policy  

E-print Network

Quantitatively analyzing human gait biomechanics will improve our ability to diagnose and treat disability and to measure the effectiveness of assistive devices. Gait analysis is one technology used to analyze walking, but ...

Tan, Junjay

2009-01-01

168

Punctuated Anytime Learning for Hexapod Gait Generation Gary B. Parker  

E-print Network

Punctuated Anytime Learning for Hexapod Gait Generation Gary B. Parker Connecticut College, New of gait generation for a hexapod robot with changing capa­ bilities. 1. Introduction In order to explore

Parker, Gary B.

169

Punctuated Anytime Learning for Hexapod Gait Generation Gary B. Parker  

E-print Network

Punctuated Anytime Learning for Hexapod Gait Generation Gary B. Parker Connecticut College, New of gait generation for a hexapod robot with changing capa- bilities. 1. Introduction In order to explore

Parker, Gary B.

170

Gait stability in children with cerebral palsy  

PubMed Central

Children with unilateral Cerebral Palsy (CP) have several gait impairments, amongst which impaired gait stability may be one. We tested whether a newly developed stability measure (the foot placement estimator, FPE) which does not require long data series, can be used to asses gait stability in typically developing (TD) children as well as children with CP. In doing so, we tested the FPE’s sensitivity to the assumptions needed to calculate this measure, as well as the ability of the FPE to detect differences in stability between children with CP and TD children, and differences in walking speed. Participants were asked to walk at two different speeds, while gait kinematics were recorded. From these data, the FPE, as well as the error that violations of assumptions of the FPE could have caused were calculated. The results showed that children with CP walked with marked instabilities in anterior-posterior and mediolateral directions. Furthermore, errors caused by violations of assumptions in calculation of FPE were only small (~1.5 cm), while effects of walking speed (~20 cm per m/s increase in walking speed) and group (~5cm) were much larger. These results suggest that the FPE may be used to quantify gait stability in TD children and children with CP. PMID:23500163

Bruijn, Sjoerd M.; Millard, Matthew; van Gestel, Leen; Meyns, Pieter; Jonkers, Ilse; Desloovere, Kaat

2013-01-01

171

A historical review of gait analysis.  

PubMed

Healthcare professionals have long been concerned with the assessment of human gait, but only recently were they able to utilize instrumental gait analysis in routine clinical practice for diagnosis, and to guide the selection of treatment methods for complex musculo-skeletal and neurological disorders. The development of motion analysis systems has progressed through several stages from simple to more sophisticated, versatile, multimodal, and accurate equipment. Several computerized motion analysis systems are now commercially available for the measurement of human gait. These vary in their design and performance. The purpose of this review is to summarize briefly the history and advances in the technology of instrumental gait analysis, especially during the past 3 decades. Further, it is hoped that this review will give clinical practitioners and researchers a general insight into the variety of measurement systems that are currently available for gait analysis and enable them to make an informed choice of the motion analysis system that best suits their clinical needs. PMID:21063300

Al-Zahrani, Khaled S; Bakheit, Magid O

2008-04-01

172

The asymmetric gait toenail unit sign.  

PubMed

The aim of this investigation was to resolve a diagnostic problem and report toenail unit changes attributable to shoe friction that resemble onychomycosis, but that are fungus-negative, and identify common skeletal causes in patients with an asymmetric walking gait. X-ray and clinical feet inspections were performed to evaluate skeletal components that change normal foot biodynamics. Forty-nine patients, all dermatophyte-negative, were reviewed. All patients were those seen in our private practice who demonstrated skeletal and toenail unit abnormalities such as onycholysis, nail bed keratosis resembling distal subungual onychomycosis, nail plate surface abnormalities, distal toe skin keratosis, a diagnostic nail plate shape, as well as several skeletal abnormalities. The clinical abnormalities of the asymmetric gait syndrome include onycholysis, nail bed keratosis, nail plate surface abnormalities, and a diagnostic nail plate shape. By the patient's history, the skeletal findings that were present worsened with age and, in many patients, they were familial. Onychomycosis does not lead to an asymmetric gait nail problem, asymmetric gait toenail does not favor dermatophyte infection, and not all nail dystrophies are the result of an asymmetric walking gait. PMID:23008938

Zaias, Nardo; Rebell, Gerbert; Casal, German; Appel, Jason

2012-01-01

173

Sporadic hyperekplexia presenting with an ataxic gait.  

PubMed

We describe a 62-year-old man with a sporadic form of hyperekplexia who presented with an unsteady gait, present since the age of 47. His clinical examination revealed an insecure broad-based gait and difficulty with tandem walking but no other abnormalities. For nearly a decade the patient was misdiagnosed with an idiopathic ataxia. A video electroencephalogram combined with an electromyogram during sudden auditory stimulus demonstrated an excessive startle response. An extensive work-up ruled out all the known causes of symptomatic hyperekplexia including anti-glycine receptor antibodies. Treatment with clonazepam markedly reduced the threshold and intensity of the startle response, enabling him to recover independence. Hyperekplexia is frequently associated with an awkward and hesitating gait, but these gait abnormalities might be confused with other causes of gait disorders if one is not aware of this disease. We report this patient to highlight that a correct diagnosis of hyperekplexia is crucial, because its treatment may change quality of life. PMID:24054400

Rouco, Idoia; Bilbao, Iker; Losada, Jose; Maestro, Iratxe; Zarranz, Juan Jose

2014-02-01

174

Simulating pathological gait using the enhanced linear inverted pendulum model  

Microsoft Academic Search

In this paper, we propose a new method to simulate human gait motion when muscles are weakened. The method is based on the enhanced version of three-dimensional linear inverted pendulum model that is used for generation of gait in robotics. After the normal gait motion is generated by setting the initial posture and the parameters that decide the trajectories of

Taku Komura; Akinori Nagano; Howard Leung; Yoshihisa Shinagawa

2005-01-01

175

Gait characteristics in individuals with intellectual disabilities: a literature review.  

PubMed

Gait is a functionally highly relevant aspect of motor performance. In the general population poorer gait increases the risk of falls and is a predictor for future disability, cognitive impairment, institutionalization and/or mortality. People with intellectual disabilities (ID) show a delayed motor development, which brings to attention the abnormalities that might accompany gait in this population throughout childhood and adulthood. Therefore, this paper aims (a) to provide a focused review of the available literature on gait characteristics in individuals with ID and (b) to gain insight into available instrumentations measuring gait in this population. We searched the database of PubMed for relevant articles and the reference lists of included articles, resulting in 44 included articles. Forty one studies reported gait characteristics during over-ground walking and six studies during perturbed walking conditions. Most studies investigated syndrome-specific ID populations, only five studies investigated the general ID population. The studies show that gait abnormalities are evident during over-ground walking in the ID population, both in people with genetic syndromes and with ID without genetic syndromes. During perturbed conditions people with ID altered their gait with stability-enhancing adaptations. Abnormalities in gait may be partly explained by physical features, but the interrelatedness between gait and cognition may also be an explanation for the gait abnormalities seen in the ID population. Further research regarding gait characteristics of the ID population, and its relation to cognitive functioning, and adverse health outcomes is needed. PMID:25105568

Almuhtaseb, Sanaa; Oppewal, Alyt; Hilgenkamp, Thessa I M

2014-11-01

176

Influence of cell phone email use on characteristics of gait  

Microsoft Academic Search

Previously, gait had been considered an automatic and rhythmical movement that uses minimal attentional resources. The relationship between attention and gait has been revealed in recent research. However, in young adults in particular, the influence of using a cell phone – which is used frequently in daily life and considered to require high attentional demands – on gait has not

Shinichi Demura; Masanobu Uchiyama

2009-01-01

177

EVOLVING LEG CYCLES TO PRODUCE HEXAPOD GAITS GARY B. PARKER  

E-print Network

EVOLVING LEG CYCLES TO PRODUCE HEXAPOD GAITS GARY B. PARKER Computer Science, Connecticut College, New London, CT 06320 parker@conncoll.edu ABSTRACT Gait generation for hexapod robots is accomplished for a simulated hexapod robot. KEYWORDS: genetic, learning, robot, hexapod, gait, control, cyclic INTRODUCTION

Parker, Gary B.

178

Statistical Analysis of Gait Rhythm in Patients With Parkinson's Disease  

Microsoft Academic Search

To assess the gait variability in patients with Parkinson's disease (PD), we first used the nonparametric Parzen-window method to estimate the probability density functions (PDFs) of stride interval and its two subphases (i.e., swing interval and stance interval). The gait rhythm standard deviation (??) parameters computed with the PDFs indicated that the gait variability is significantly increased in PD. Signal

Yunfeng Wu; Sridhar Krishnan

2010-01-01

179

Effect of silhouette quality on hard problems in gait recognition  

Microsoft Academic Search

Gait as a behavioral biometric has been the subject of recent investigations. However, understanding the limits of gait-based recognition and the quantitative study of the factors effecting gait have been confounded by errors in the extracted silhouettes, upon which most recognition algorithms are based. To enable us to study this effect on a large population of subjects, we present a

Zongyi Liu; Sudeep Sarkar

2005-01-01

180

Smart Insole: A Wearable System for Gait Analysis Electrical Engineering  

E-print Network

of the natural gait model. In this paper, we present a novel portable system, called Smart Insole, to address surgery, and the corresponding treatment and training can be customized according to an individual the Gait Lab. A standard gait lab is roughly a 1200 square foot facility. In order to achieve com

He, Lei

181

Virtual gait training for children with cerebral palsy using the Lokomat gait orthosis.  

PubMed

The Lokomat gait orthosis was developed in the Spinal Cord Injury Center at the University Hospital Balgrist Zurich and provides automatic gait training for patients with neurological gait impairments, such as Cerebral Palsy (CP). Each patient undergoes a task-oriented Lokomat rehabilitation training program via a virtual reality setup. In four virtual scenarios, the patient is able to exercise tasks such as wading through water, playing soccer, overstepping obstacles or training in a street scenario, each task offering varying levels of difficulty. Patients provided positive feedback in reference to the utilized haptic method, specifically addressing the sufficient degree of realism. In a single case study, we verified the task difficulty. PMID:18391287

Koenig, Alexander; Wellner, Mathias; Köneke, Susan; Meyer-Heim, Andreas; Lünenburger, Lars; Riener, Robert

2008-01-01

182

Cave Bear  

NSDL National Science Digital Library

Decoding an ancient cave bear. A two-ton, thirteen-foot cave bear, extinct for ten thousand years, has just experienced a rebirth of sorts. From a tooth and a bone, scientists have recovered its entire genetic code.Eddy Rubin, director of the Department of Energy's Joint Genome Institute, says finding genuine cave bear DNA was like looking for a needle in a haystack. The haystack were all the other organisms that were living in the bones and in the tooth of this ancient creature. And the needle was the little bit of the ancient creature's genome DNA, or genes.They used state-of-the-art computer technology to separate the bear genes from the clutter. Jurassic Park fans should note that they can't clone a new cave bear, nor can they recover DNA from creatures as old as the dinosaurs. But they do hope to reconstruct the genetic code of Neanderthals, our closest non-human relatives, to better understand how our own species evolved. This resource contains detailed text description of the research as well as likes for further inquiry.

American Association for the Advancement of Science (;)

2005-08-15

183

Gait asymmetry detection in older adults using a light ear-worn sensor.  

PubMed

Measuring gait asymmetry is an important feature when characterizing functional imbalance between limbs. This could be due to pathologies, such as osteoarthritis, stroke, or associated with the effects of surgeries such as hip arthroplasty. Generally, the study of asymmetry or imbalance has required the use of a gait lab or force plates, which could be expensive and difficult to use in home settings. This work validates the use of a light weight ear sensor (7.4 g) with an instrumented treadmill for 64 subjects (age (60.04 (15.36)) including healthy subjects (14) as well as subjects who had been treated for hip (17), knee-replacement surgery (21) and knee osteoarthritis (12). Subjects performed treadmill walking at several speeds on flat surfaces, inclines and declines. Accelerometer data from the ear sensor were segmented into consecutive steps and temporal features were extracted. The measures of gait cycle time and step-period asymmetry obtained from the ear sensor matched well those of the treadmill for flat surfaces, inclines and declines. The key implication of the study is that the proposed method could replace expensive equipment for monitoring temporal gait features in clinics as well as free-living environments, which is important for monitoring rehabilitation after surgery and the progress of diseases affecting limb imbalance. PMID:24711048

Atallah, L; Wiik, A; Lo, B; Cobb, J P; Amis, A A; Yang, G-Z

2014-05-01

184

Gait evaluation of biofeedback balance training for chronic stroke patients  

Microsoft Academic Search

Uneven weight bearing distribution, which leads to asymmetric characteristics of the locomotor pattern, is commonly observed among patients with hemiparesis during quasistatic stance. The purpose of this research was to investigate the effects of using a visual and auditory biofeedback system in a balance retraining program for patients in the chronic post?stroke period. Sixteen chronic patients with hemiparesis who suffered

2003-01-01

185

Gait identification from invisible shadows  

NASA Astrophysics Data System (ADS)

This paper introduces a person identification system that uses as input the shadow images of a walking person, as projected by multiple lights(in this application invisible/infrared lights); the system uses a database of examples of shadows images of a number of people who walk. While it is accepted that personal identification has a higher correct classification rate if views from multiple cameras are used, most systems use only one camera, mainly because (i) Installation in real-world environments is easier, less cameras and no need to synchronize cameras, (ii) Computational cost is reduced. In the proposed system, we obtain the advantages of multiple viewpoints with a single camera and additional light sources. More specific, we install multiple infrared lights to project shadows of a subject on the ground and a camera with an infrared transmitting filter mounted in the ceiling inside of a building. Shadow areas, which are projections of one's body on the ground by multiple lights, can be considered as body areas captured from different viewpoints; thus, the proposed system is able to capture multiple projections of the body from a single camera. We explored in other papers the use of sunproduced shadow for identification of people walking freely in the outdoor. In this paper the application scenario is a system installed at the airport in the areas that precedes the immigration checkpoint. Japan already has health monitoring cameras focused on approaching individuals, to determine their health condition; the here described system would also be installed in such a controlled area with restricted walk corridors of walk and controlled lighting. Gait is a remote biometrics and can provide early warning; on another hand it can be used as corroborating evidence in a multi-modal biometrics system. A database of images including shadows for a set of 28 walking people was collected, and the features extracted from shadow areas by affine moment invariants, after which identification of the subject followed. The experiments using the database show the effectiveness of the proposed method and further prove the superiority of using multiple viewpoints compared to a single viewpoint.

Iwashita, Yumi; Uchino, Koji; Kurazume, Ryo; Stoica, Adrian

2012-06-01

186

Basic gait analysis based on continuous wave radar.  

PubMed

A gait analysis method based on continuous wave (CW) radar is proposed in this paper. Time-frequency analysis is used to analyze the radar micro-Doppler echo from walking humans, and the relationships between the time-frequency spectrogram and human biological gait are discussed. The methods for extracting the gait parameters from the spectrogram are studied in depth and experiments on more than twenty subjects have been performed to acquire the radar gait data. The gait parameters are calculated and compared. The gait difference between men and women are presented based on the experimental data and extracted features. Gait analysis based on CW radar will provide a new method for clinical diagnosis and therapy. PMID:22951210

Zhang, Jun

2012-09-01

187

Recovery of Gait After Stroke: What Changes?  

Microsoft Academic Search

Background. Little is known about whether changes in coordination patterns of muscle activation after stroke are related to functional recovery of walking. Objective . The present study investigated the longitudinal relationship between changes in neuromuscular activation patterns of paretic muscles in hemiplegic gait and improvement in walking ability after stroke. Methods. Thirteen patients diagnosed with a first unilateral ischemic stroke

Jaap H. Buurke; Anand V. Nene; Gert Kwakkel; Victorien Erren-Wolters; Maarten J. IJzerman; Hermie J. Hermens

2008-01-01

188

Punctuated anytime learning for hexapod gait generation  

Microsoft Academic Search

Punctuated anytime learning is presented as the solution for two problems: the use of anytime learning with an off-line learning module and the linking of the actual robot to its simulation during evolutionary robotics. Two methods of punctuated anytime learning, fitness biasing and the co-evolution of model parameters, are described and compared using the common task of gait generation for

Gary B. Parker

2002-01-01

189

The computer era in gait analysis.  

PubMed

This article traces the history of the use of computers in the analysis of human gait. Following a brief retrospective review of the precomputer era, the topics of motion, force, and pressure analysis using computers are discussed. The need for careful justification of clinically applied techniques is stressed throughout, and some future trends are anticipated. PMID:8364850

Cavanagh, P R; Henley, J D

1993-07-01

190

Gait-Based Human Age Estimation  

Microsoft Academic Search

We investigate in this paper the problem of estimating human ages from gait signatures. To our knowledge, this problem has not been formally addressed in the literature. Estimating human ages at a distance has a number of potential applications, including visual surveillance and monitoring in such public places as airports, railway stations, shopping malls, and various building entrances. Motivated by

Jiwen Lu; Yap-peng Tan

2010-01-01

191

ORIGINAL ARTICLE Prevalence of Specific Gait Abnormalities  

E-print Network

ORIGINAL ARTICLE Prevalence of Specific Gait Abnormalities in Children With Cerebral Palsy Influence of Cerebral Palsy Subtype, Age, and Previous Surgery Tishya A. L. Wren, PhD,* Susan Rethlefsen, PT. These findings provide important information for counsel- ing ambulatory children with cerebral palsy

Valero-Cuevas, Francisco

192

A practical gait analysis system using gyroscopes  

Microsoft Academic Search

This study investigated the possibility of using uni-axial gyroscopes to develop a simple portable gait analysis system. Gyroscopes were attached on the skin surface of the shank and thigh segments and the angular velocity for each segment was recorded in each segment. Segment inclinations and knee angle were derived from segment angular velocities. The angular signals from a motion analysis

Kaiyu Tong; Malcolm H Granat

1999-01-01

193

Bear Bones  

NSDL National Science Digital Library

An estimated ten million Americans have osteoporosis, an age-related disease in which the bones gradually become brittle and weak. Now, scientists are looking to animals for clues on how to combat this condition. This resource describes the study of sustaining bone strength of hibernating bears.

Science Update;

2004-03-08

194

Kinetic changes in gait during low magnitude military load carriage.  

PubMed

Indian infantry soldiers carry smaller magnitudes of loads for operational requirements. The ground reaction forces (GRFs) and impulse responses of 10 healthy male Indian infantry soldiers were collected while they walked carrying operational loads between 4.2 and 17.5 kg (6.5-27.2% of mean body weight (BW)) and a control condition of no external load (NL). The GRF and impulse components were normalised for BW, and data for each load condition were compared with NL in each side applying one-way analysis of variance followed by Dunnett's post hoc test. Right foot data were compared with corresponding left foot GRF data for all load conditions and NL. There were significant increases in vertical and anteroposterior GRFs with increase in load. Left and right feet GRF data in corresponding load conditions were significantly different in anteroposterior plane. No significant change was observed in the temporal components of support phase of gait. Changes in impulse parameter were observed in the anteroposterior and vertical planes while carrying load greater than 23 and 16.6% of BW for the right foot and left foot, respectively. Result indicates that smaller magnitudes of loads produced kinetic changes proportional to system weight, similar to heavier loads with the possibility of increased injury risk. Observed smaller asymmetric changes in gait may be considered as postural adjustment due to load. Unique physical characteristics of Indian soldiers and the probable design shortcomings of the existing backpack might have caused significant changes in GRF and peak impulse during smaller load carriage. PMID:24164415

Majumdar, Deepti; Pal, Madhu Sudan; Pramanik, Anilendu; Majumdar, Dhurjati

2013-01-01

195

Development and testing of the Gait Assessment and Intervention Tool (G.A.I.T.): a measure of coordinated gait components.  

PubMed

Recent neuroscience methods have provided the basis upon which to develop effective gait training methods for recovery of the coordinated components of gait after neural injury. We determined that there was not an existing observational measure that was, at once, adequately comprehensive, scored in an objectively-based manner, and capable of assessing incremental improvements in the coordinated components of gait. Therefore, the purpose of this work was to use content valid procedures in order to develop a relatively inexpensive, more comprehensive measure, scored with an objectively-based system, capable of incrementally scoring improvements in given items, and that was both reliable and capable of discriminating treatment response for those who had a stroke. Eight neurorehabilitation specialists developed criteria for the gait measure, item content, and scoring method. In subjects following stroke (>12 months), the new measure was tested for intra- and inter-rater reliability using the Intraclass Correlation Coefficient; capability to detect treatment response using Wilcoxon Signed Ranks Test; and discrimination between treatment groups, using the Plum Ordinal Regression. The Gait Assessment and Intervention Tool (G.A.I.T.) is a 31-item measure of the coordinated movement components of gait and associated gait deficits. It exhibited the following advantages: comprehensive, objective-based scoring method, incremental measurement of improvement within given items. The G.A.I.T. had good intra- and inter-rater reliability (ICC=.98, p=.0001, 95% CI=.95, .99; ICC=.83, p=.007, 95% CI=.32, .96, respectively. The inexperienced clinician who had training, had an inter-rater reliability with an experienced rater of ICC=.99 (p=.0001, CI=.97, .999). The G.A.I.T. detected improvement in response to gait training for two types of interventions: comprehensive gait training (z=-2.93, p=.003); and comprehensive gait training plus functional electrical stimulation (FES; z=-3.3, p=.001). The G.A.I.T. was capable of discriminating between two gait training interventions, showing an additive advantage of FES to otherwise comparable comprehensive gait training (parameter estimate=1.72, p=.021; CI, .25, 3.1). PMID:19146879

Daly, J J; Nethery, J; McCabe, J P; Brenner, I; Rogers, J; Gansen, J; Butler, K; Burdsall, R; Roenigk, K; Holcomb, J

2009-04-15

196

Comparison of Gait Aspects According to FES Stimulation Position Applied to Stroke Patients  

PubMed Central

[Purpose] This study sought to identify the gait aspects according to the FES stimulation position in stroke patients during gait training. [Subjects and Methods] To perform gait analysis, ten stroke patients were grouped based on 4 types of gait conditions: gait without FES stimulation (non-FES), gait with FES stimulation on the tibialis anterior (Ta), gait with FES stimulation on the tibialis anterior and quadriceps (TaQ), and gait with FES stimulation on the tibialis anterior and gluteus medius (TaGm). [Results] Based on repeated measures analysis of variance of measurements of gait aspects comprised of gait speed, gait cycle, and step length according to the FES stimulation position, the FES stimulation significantly affected gait aspects. [Conclusion] In conclusion, stimulating the tibialis anterior and quadriceps and stimulating the tibialis anterior and gluteus medius are much more effective than stimulating only the tibialis anterior during gait training in stroke patients using FES. PMID:24764634

Mun, Byeong-mu; Kim, Tae-ho; Lee, Jin-hwan; Lim, Jin-youg; Seo, Dong-kwon; Lee, Dong-jin

2014-01-01

197

Kinematic Analysis Quantifies Gait Abnormalities Associated with Lameness in Broiler Chickens and Identifies Evolutionary Gait Differences  

PubMed Central

This is the first time that gait characteristics of broiler (meat) chickens have been compared with their progenitor, jungle fowl, and the first kinematic study to report a link between broiler gait parameters and defined lameness scores. A commercial motion-capturing system recorded three-dimensional temporospatial information during walking. The hypothesis was that the gait characteristics of non-lame broilers (n?=?10) would be intermediate to those of lame broilers (n?=?12) and jungle fowl (n?=?10, tested at two ages: immature and adult). Data analysed using multi-level models, to define an extensive range of baseline gait parameters, revealed inter-group similarities and differences. Natural selection is likely to have made jungle fowl walking gait highly efficient. Modern broiler chickens possess an unbalanced body conformation due to intense genetic selection for additional breast muscle (pectoral hypertrophy) and whole body mass. Together with rapid growth, this promotes compensatory gait adaptations to minimise energy expenditure and triggers high lameness prevalence within commercial flocks; lameness creating further disruption to the gait cycle and being an important welfare issue. Clear differences were observed between the two lines (short stance phase, little double-support, low leg lift, and little back displacement in adult jungle fowl; much double-support, high leg lift, and substantial vertical back movement in sound broilers) presumably related to mass and body conformation. Similarities included stride length and duration. Additional modifications were also identified in lame broilers (short stride length and duration, substantial lateral back movement, reduced velocity) presumably linked to musculo-skeletal abnormalities. Reduced walking velocity suggests an attempt to minimise skeletal stress and/or discomfort, while a shorter stride length and time, together with longer stance and double-support phases, are associated with instability. We envisage a key future role for this highly quantitative methodology in pain assessment (associated with broiler lameness) including experimental examination of therapeutic agent efficacy. PMID:22815823

Caplen, Gina; Hothersall, Becky; Murrell, Joanna C.; Nicol, Christine J.; Waterman-Pearson, Avril E.; Weeks, Claire A.; Colborne, G. Robert

2012-01-01

198

Clinical Gait assessment of older adults using open platform tools.  

PubMed

Gait impairment is associated with increased falls risk. The gait of 321 community dwelling elderly adults was assessed using the TRIL Gait Analysis Platform (GAP), which was specially designed for ease of use in a research clinic setting by non-experts. The GAP featured body-worn kinematic sensors, a pressure sensitive electronic walkway, and two orthogonally mounted web cameras, and was developed using open platform tools. This flexible platform was applied to objectively measure gait parameters in different gait assessments. The results from the 6 meter walk assessment are presented here. In this assessment, participants were categorized by clinical falls history as 'fallers' or 'non-fallers'. Temporal and spatial gait parameters were examined. Significant differences in spatial parameters were observed when fallers and non-fallers were compared. Temporal parameters were found to differ, though not significantly. PMID:22254348

Scanaill, Cliodhna Ni; Greene, Barry R; Doheny, Emer P; O'Donovan, Karol; O'Shea, Terrance; O'Donovan, Alan D; Foran, Tim; Cunningham, Clodagh; Kenny, Rose Anne

2011-01-01

199

RELATIONSHIP OF GAIT AND COGNITION IN THE ELDERLY  

PubMed Central

Gait and cognitive impairments in older adults mostly reflect the co-occurrence of two geriatric syndromes linked by common underlying brain substrates and pathologies. Gait control is predominately mediated by frontal subcortical circuits, which overlap with circuits controlling executive control and attention functions. These circuits are vulnerable to multiple age-related pathologies such as ischemia, inflammation, and neurodegeneration, which could ultimately cause cognitive, gait, or combined cognitive and gait impairments. The following review aims to describe various gait and cognitive classifications, gait based phenotypes, common underlying pathological processes, and provide a link between motor and cognitive impairments in an effort to predict the risk of dementia, as well as remediate impairments by applying appropriate interventions. PMID:24349877

Parihar, Raminder; Mahoney, Jeannette R.; Verghese, Joe

2013-01-01

200

Treatment of gait ignition failure with ropinirole.  

PubMed

Gait ignition failure (GIF) is a syndrome characterized by hesitation or inability to initiate gait from a static position. It may occur in a variety of conditions, including normal pressure hydrocephalus, subcortical vascular disease, parkinsonian syndromes and a variety of focal lesions. Previous information on the treatment of GIF has been primarily anecdotal, but there have been a few reports of response to dopamine agonists. We report a 63-year-old man with anoxic encephalopathy who developed GIF nine years after the initial anoxic insult. The patient's GIF responded robustly, albeit transiently, to ropinirole. MRI was unrevealing, but a positron emission tomography scan showed hypometabolism in the deep frontal ACA/MCA watershed area; this may have disconnected the basal ganglia from the motor cortex and/or interrupted dopaminergic mesocortical transmission. Our understanding of the pathophysiology and the treatment of GIF remains limited, but there may be at least a limited therapeutic role for dopamine agonists. PMID:25360234

Cohen-Oram, Alexis N; Stewart, Jonathan T; Bero, Kim; Hoffmann, Michael W

2014-10-01

201

Treatment of Gait Ignition Failure with Ropinirole  

PubMed Central

Gait ignition failure (GIF) is a syndrome characterized by hesitation or inability to initiate gait from a static position. It may occur in a variety of conditions, including normal pressure hydrocephalus, subcortical vascular disease, parkinsonian syndromes and a variety of focal lesions. Previous information on the treatment of GIF has been primarily anecdotal, but there have been a few reports of response to dopamine agonists. We report a 63-year-old man with anoxic encephalopathy who developed GIF nine years after the initial anoxic insult. The patient’s GIF responded robustly, albeit transiently, to ropinirole. MRI was unrevealing, but a positron emission tomography scan showed hypometabolism in the deep frontal ACA/MCA watershed area; this may have disconnected the basal ganglia from the motor cortex and/or interrupted dopaminergic mesocortical transmission. Our understanding of the pathophysiology and the treatment of GIF remains limited, but there may be at least a limited therapeutic role for dopamine agonists. PMID:25360234

Cohen-Oram, Alexis N.; Stewart, Jonathan T.; Bero, Kim; Hoffmann, Michael W.

2014-01-01

202

Female gait patterns: The influence of footwear  

Microsoft Academic Search

The two horizontal orthogonal ground reaction forces, mediolateral (Fx) and antero-posterior (Fy), together with limb segment displacements, were recorded simultaneously during gait from 24 female subjects aged 18–29 years. Recordings were made for each subject barefoot and when wearing each of four different pairs of shoes: soft-soled, rigid-soled, medium- and high-heeled. The results showed a trend for increasing lateral stability

R. W. SOAMES; A. A. EVANS

1987-01-01

203

Coupled nonlinear oscillators and the symmetries of animal gaits  

Microsoft Academic Search

Summary  Animal locomotion typically employs several distinct periodic patterns of leg movements, known as gaits. It has long been\\u000a observed that most gaits possess a degree of symmetry. Our aim is to draw attention to some remarkable parallels between the\\u000a generalities of coupled nonlinear oscillators and the observed symmetries of gaits, and to describe how this observation might\\u000a impose constraints on

J. J. Collins; I. N. Stewart

1993-01-01

204

Hamstring and psoas length of crouch gait in cerebral palsy: a comparison with induced crouch gait in age- and sex-matched controls  

PubMed Central

Background Previous studies have shown that hamstring lengths are often not short in patients with cerebral palsy, which raises concerns over the benefits of distal hamstring lengthening in patients with crouch gait. In this study, the authors measured lengths of hamstrings and psoas muscles in normal subjects mimicking crouch gait and compared these with lengths in cerebral palsy patients with crouch gait. Methods Thirty-six patients with cerebral palsy and crouch gait were included in this study, and in addition, 36 age- and sex-matched normal controls were recruited. Hamstring and psoas muscle lengths in patients were evaluated using gait analysis and interactive musculoskeletal modeling software. Muscle lengths were also measured in the normal control group during normal gait and while mimicking crouch gait, and these were compared with those of cerebral palsy patient with crouch gait. Results No significant differences were observed between maximum hamstring (p=0.810) and maximum psoas (p=0.456) lengths of patients and controls mimicking crouch gait. However, patients showed significantly shorter excursions of hamstring (p=0.022) and psoas (p=0.036) muscles than controls, whereas no significant excursion differences were observed between controls during normal gait and mimicking crouch gait. Conclusions Normal controls mimicking crouch gait and cerebral palsy patients with crouch gait demonstrate similar muscle length patterns. However, mimicked crouch gait did not reproduce the excursion pattern shown by patients with crouch gait, which suggests that reduced hamstring and psoas excursion is an innate characteristic of pathologic crouch gait. PMID:23363928

2013-01-01

205

Fractional Langevin model of gait variability  

PubMed Central

The stride interval in healthy human gait fluctuates from step to step in a random manner and scaling of the interstride interval time series motivated previous investigators to conclude that this time series is fractal. Early studies suggested that gait is a monofractal process, but more recent work indicates the time series is weakly multifractal. Herein we present additional evidence for the weakly multifractal nature of gait. We use the stride interval time series obtained from ten healthy adults walking at a normal relaxed pace for approximately fifteen minutes each as our data set. A fractional Langevin equation is constructed to model the underlying motor control system in which the order of the fractional derivative is itself a stochastic quantity. Using this model we find the fractal dimension for each of the ten data sets to be in agreement with earlier analyses. However, with the present model we are able to draw additional conclusions regarding the nature of the control system guiding walking. The analysis presented herein suggests that the observed scaling in interstride interval data may not be due to long-term memory alone, but may, in fact, be due partly to the statistics. PMID:16076394

West, Bruce J; Latka, Miroslaw

2005-01-01

206

Evaluating alternative gait strategies using evolutionary robotics  

PubMed Central

Evolutionary robotics is a branch of artificial intelligence concerned with the automatic generation of autonomous robots. Usually the form of the robot is predefined and various computational techniques are used to control the machine's behaviour. One aspect is the spontaneous generation of walking in legged robots and this can be used to investigate the mechanical requirements for efficient walking in bipeds. This paper demonstrates a bipedal simulator that spontaneously generates walking and running gaits. The model can be customized to represent a range of hominoid morphologies and used to predict performance parameters such as preferred speed and metabolic energy cost. Because it does not require any motion capture data it is particularly suitable for investigating locomotion in fossil animals. The predictions for modern humans are highly accurate in terms of energy cost for a given speed and thus the values predicted for other bipeds are likely to be good estimates. To illustrate this the cost of transport is calculated for Australopithecus afarensis. The model allows the degree of maximum extension at the knee to be varied causing the model to adopt walking gaits varying from chimpanzee-like to human-like. The energy costs associated with these gait choices can thus be calculated and this information used to evaluate possible locomotor strategies in early hominids. PMID:15198699

Sellers, William I; Dennis, Louise A; Wang, W -J; Crompton, Robin H

2004-01-01

207

Gait Signal Analysis with Similarity Measure  

PubMed Central

Human gait decision was carried out with the help of similarity measure design. Gait signal was selected through hardware implementation including all in one sensor, control unit, and notebook with connector. Each gait signal was considered as high dimensional data. Therefore, high dimensional data analysis was considered via heuristic technique such as the similarity measure. Each human pattern such as walking, sitting, standing, and stepping up was obtained through experiment. By the results of the analysis, we also identified the overlapped and nonoverlapped data relation, and similarity measure analysis was also illustrated, and comparison with conventional similarity measure was also carried out. Hence, nonoverlapped data similarity analysis provided the clue to solve the similarity of high dimensional data. Considered high dimensional data analysis was designed with consideration of neighborhood information. Proposed similarity measure was applied to identify the behavior patterns of different persons, and different behaviours of the same person. Obtained analysis can be extended to organize health monitoring system for specially elderly persons. PMID:25110724

Shin, Seungsoo

2014-01-01

208

Self in motion: sensorimotor and cognitive mechanisms in gait agency.  

PubMed

Acting in our environment and experiencing ourselves as conscious agents are fundamental aspects of human selfhood. While large advances have been made with respect to understanding human sensorimotor control from an engineering approach, knowledge about its interaction with cognition and the conscious experience of movement (agency) is still sparse, especially for locomotion. We investigated these relationships by using life-size visual feedback of participants' ongoing locomotion, thereby extending agency research previously limited to goal-directed upper limb movements to continuous movements of the entire body. By introducing temporal delays and cognitive loading we were able to demonstrate distinct effects of bottom-up visuomotor conflicts as well as top-down cognitive loading on the conscious experience of locomotion (gait agency) and gait movements. While gait agency depended on the spatial and temporal congruency of the avatar feedback, gait movements were solely driven by its temporal characteristics as participants nonconsciously attempted to synchronize their gait with their avatar's gait. Furthermore, gait synchronization was suppressed by cognitive loading across all tested delays, whereas gait agency was only affected for selective temporal delays that depended on the participant's step cycle. Extending data from upper limb agency and auditory gait agency, our results are compatible with effector-independent and supramodal control of agency; they show that both mechanisms are dissociated from automated sensorimotor control and that cognitive loading further enhances this dissociation. PMID:23825398

Kannape, O A; Blanke, O

2013-10-01

209

Enhanced data consistency of a portable gait measurement system.  

PubMed

A gait measurement system is a useful tool for rehabilitation applications. Such a system is used to conduct gait experiments in large workplaces such as laboratories where gait measurement equipment can be permanently installed. However, a gait measurement system should be portable if it is to be used in clinics or community centers for aged people. In a portable gait measurement system, the workspace is limited and landmarks on a subject may not be visible to the cameras during experiments. Thus, we propose a virtual-marker function to obtain positions of unseen landmarks for maintaining data consistency. This work develops a portable clinical gait measurement system consisting of lightweight motion capture devices, force plates, and a walkway assembled from plywood boards. We evaluated the portable clinic gait system with 11 normal subjects in three consecutive days in a limited experimental space. Results of gait analysis based on the verification of within-day and between-day coefficients of multiple correlations show that the proposed portable gait system is reliable. PMID:24289412

Lin, Hsien-I; Chiang, Y P

2013-11-01

210

Detection of abnormalities in a human gait using smart shoes  

NASA Astrophysics Data System (ADS)

Health monitoring systems require a means for detecting and quantifying abnormalities from measured signals. In this paper, a new method for detecting abnormalities in a human gait is proposed for an improved gait monitoring system for patients with walking problems. In the previous work, we introduced a fuzzy logic algorithm for detecting phases in a human gait based on four foot pressure sensors for each of the right and left foot. The fuzzy logic algorithm detects the gait phases smoothly and continuously, and retains all information obtained from sensors. In this paper, a higher level algorithm for detecting abnormalities in the gait phases obtained from the fuzzy logic is discussed. In the proposed algorithm, two major abnormalities are detected 1) when the sensors measure improper foot pressure patterns, and 2) when the human does not follow a natural sequence of gait phases. For mathematical realization of the algorithm, the gait phases are dealt with by a vector analysis method. The proposed detection algorithm is verified by experiments on abnormal gaits as well as normal gaits. The experiment makes use of the Smart Shoes that embeds four bladders filled with air, the pressure changes in which are detected by pressure transducers.

Kong, Kyoungchul; Bae, Joonbum; Tomizuka, Masayoshi

2008-03-01

211

Gait analysis of a radial symmetrical hexapod robot based on parallel mechanisms  

NASA Astrophysics Data System (ADS)

Most gait studies of multi-legged robots in past neglected the dexterity of robot body and the relationship between stride length and body height. This paper investigates the performance of a radial symmetrical hexapod robot based on the dexterity of parallel mechanism. Assuming the constraints between the supporting feet and the ground with hinges, the supporting legs and the hexapod body are taken as a parallel mechanism, and each swing leg is regarded as a serial manipulator. The hexapod robot can be considered as a series of hybrid serial-parallel mechanisms while walking on the ground. Locomotion performance can be got by analyzing these equivalent mechanisms. The kinematics of the whole robotic system is established, and the influence of foothold position on the workspace of robot body is analyzed. A new method to calculate the stride length of multi-legged robots is proposed by analyzing the relationship between the workspaces of two adjacent equivalent parallel mechanisms in one gait cycle. Referring to service region and service sphere, weight service sphere and weight service region are put forward to evaluate the dexterity of robot body. The dexterity of single point in workspace and the dexterity distribution in vertical and horizontal projection plane are demonstrated. Simulation shows when the foothold offset goes up to 174 mm, the dexterity of robot body achieves its maximum value 0.1644 in mixed gait. The proposed methods based on parallel mechanisms can be used to calculate the stride length and the dexterity of multi-legged robot, and provide new approach to determine the stride length, body height, footholds in gait planning of multi-legged robot.

Xu, Kun; Ding, Xilun

2014-08-01

212

Nonlinear Dynamics of a Rotor Supported by Homopolar Magnetic Bearings with Saturation  

E-print Network

An objective in the design of high performance machinery is to minimize weight so magnetic bearings are often designed to operate slightly lower than the magnetic material saturation. Further weight reduction in the bearings requires operation...

Kang, Kyungdae

2011-02-22

213

Alterations in gait speed and age do not fully explain the changes in gait mechanics associated with healthy older women.  

PubMed

Older adults exhibit modified gait patterns compared to the young, adopting movement strategies in response to changes in musculoskeletal function. Investigating the functional mobility of older women is particularly important because of their increased life expectancy and greater falls risk compared to men. We explored the relationships between gait parameters and age in healthy older women whilst accounting for declining gait speeds. Kinematic and kinetic data were collected from thirty-nine women (60-83 years) whilst walking at a comfortable cadence. Regression analysis assessed the capacity of gait speed and age to explain the variance in gait associated with older age. Speed explained the majority of variance in many gait parameters. By including age in the regression, the total explained variance (R2) for foot clearance (70%), ankle plantarflexion angle (30%), peak ankle plantarflexor moment (58%), and hip power generation (56%) were significantly (p<0.05) greater than for speed alone. Nonetheless, changes in speed and age did not fully explain the variance in gait mechanics associated with older age and other contributing factors must exist. Losses of 1.2%/year in gait speed were predicted by age, exceeding previous predictions of -0.7%/year. Furthermore, the accumulation of apparently small decreases of 0.2 cm/year in peak foot-to-ground clearance has clinical implications and offers insight into the mechanisms by which gait becomes hazardous in older age. PMID:23122897

Alcock, L; Vanicek, N; O'Brien, T D

2013-04-01

214

Cryogenic turbopump bearing materials  

NASA Technical Reports Server (NTRS)

Materials used for modern cryogenic turbopump bearings must withstand extreme conditions of loads and speeds under marginal lubrication. Naturally, these extreme conditions tend to limit the bearing life. It is possible to significantly improve the life of these bearings, however, by improving the fatigue and wear resistance of bearing alloys, and improving the strength, liquid oxygen compatibility and lubricating ability of the bearing cage materials. Improved cooling will also help to keep the bearing temperatures low and hence prolong the bearing life.

Bhat, Biliyar N.

1989-01-01

215

Quantitative Gait Measurement With Pulse-Doppler Radar for Passive In-Home Gait Assessment  

PubMed Central

In this paper, we propose a pulse-Doppler radar system for in-home gait assessment of older adults. A methodology has been developed to extract gait parameters including walking speed and step time using Doppler radar. The gait parameters have been validated with a Vicon motion capture system in the lab with 13 participants and 158 test runs. The study revealed that for an optimal step recognition and walking speed estimation, a dual radar set up with one radar placed at foot level and the other at torso level is necessary. An excellent absolute agreement with intraclass correlation coefficients of 0.97 was found for step time estimation with the foot level radar. For walking speed, although both radars show excellent consistency they all have a system offset compared to the ground truth due to walking direction with respect to the radar beam. The torso level radar has a better performance (9% offset on average) in the speed estimation compared to the foot level radar (13%–18% offset). Quantitative analysis has been performed to compute the angles causing the systematic error. These lab results demonstrate the capability of the system to be used as a daily gait assessment tool in home environments, useful for fall risk assessment and other health care applications. The system is currently being tested in an unstructured home environment. PMID:24771566

Skubic, Marjorie; Rantz, Marilyn; Cuddihy, Paul E.

2014-01-01

216

Assessing the Temporal Relationship Between Cognition and Gait: Slow Gait Predicts Cognitive Decline in the Mayo Clinic Study of Aging  

PubMed Central

Background. The association between gait speed and cognition has been reported; however, there is limited knowledge about the temporal associations between gait slowing and cognitive decline among cognitively normal individuals. Methods. The Mayo Clinic Study of Aging is a population-based study of Olmsted County, Minnesota, United States, residents aged 70–89 years. This analysis included 1,478 cognitively normal participants who were evaluated every 15 months with a nurse visit, neurologic evaluation, and neuropsychological testing. The neuropsychological battery used nine tests to compute domain-specific (memory, language, executive function, and visuospatial skills) and global cognitive z-scores. Timed gait speed (m/s) was assessed over 25 feet (7.6 meters) at a usual pace. Using mixed models, we examined baseline gait speed (continuous and in quartiles) as a predictor of cognitive decline and baseline cognition as a predictor of gait speed changes controlling for demographics and medical conditions. Results. Cross-sectionally, faster gait speed was associated with better performance in memory, executive function, and global cognition. Both cognitive scores and gait speed declined over time. A faster gait speed at baseline was associated with less cognitive decline across all domain-specific and global scores. These results were slightly attenuated after excluding persons with incident mild cognitive impairment or dementia. By contrast, baseline cognition was not associated with changes in gait speed. Conclusions. Our study suggests that slow gait precedes cognitive decline. Gait speed may be useful as a reliable, easily attainable, and noninvasive risk factor for cognitive decline. PMID:23250002

2013-01-01

217

Passivity Based Control Of The Compass Gait Biped  

Microsoft Academic Search

. In this paper we discuss the passivity based control of the two-link robotknown as the Compass Gait Biped. Starting from a narrow region of initial conditions,the compass gait biped is capable of locomotion down shallow inclines without actuationor feedback control of any kind. We will discuss some feedback control strategiesthat can exploit these passive dynamics by shaping the energy

Mark W. Spong

1999-01-01

218

Humanoid Soccer Gait Generation and Optimization Using Probability Distribution Models  

E-print Network

Humanoid Soccer Gait Generation and Optimization Using Probability Distribution Models Changjiu constructed by the permutation of optimization parameters to establish a periodic orbit in biped locomotion to generate and optimize various types of basic soccer-playing humanoid gaits for our humanoid soccer robot

Menegatti, Emanuele

219

Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis  

E-print Network

Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis JEFFREY M. HAUSDORFF,1 of altered gait rhythm in amyotrophic lateral sclerosis. J Appl Physiol 88: 2045­ 2053, 2000.--Amyotrophic dynamics AMYOTROPHIC LATERAL SCLEROSIS (ALS) is a disorder primarily affecting the motoneurons

220

Spatial, temporal and muscle action patterns of Tai Chi gait  

Microsoft Academic Search

This study was to quantitatively characterize the spatial, temporal, and neuromuscular activation patterns of Tai Chi gait (TCG). Ten healthy young subjects were tested. The kinematics of TCG and normal gait (NG) were measured using a marker-based motion analysis system and two biomechanical force plates. Surface electromyography (EMG) was recorded from six left-side muscles: tibialis anterior, soleus, peronaeus longus, rectus

Ge Wu; Wei Liu; Juvena Hitt; Debra Millon

2004-01-01

221

Gait posture estimation using wearable acceleration and gyro sensors  

Microsoft Academic Search

A method for gait analysis using wearable acceleration sensors and gyro sensors is proposed in this work. The volunteers wore sensor units that included a tri-axis acceleration sensor and three single axis gyro sensors. The angular velocity data measured by the gyro sensors were used to estimate the translational acceleration in the gait analysis. The translational acceleration was then subtracted

Ryo Takeda; Shigeru Tadano; Akiko Natorigawa; Masahiro Todoh; Satoshi Yoshinari

2009-01-01

222

Dynamic knee loads during gait predict proximal tibial bone distribution  

Microsoft Academic Search

This study tested the validity of the prediction of dynamic knee loads based on gait measurements. The relationship between the predicted loads at the knee and the distribution of bone between the medial and lateral sides of the tibia was examined. The motion and external forces and moments at the knee were measured during gait and a statically determinate muscle

Debra E. Hurwitz; Dale R. Sumner; Thomas P. Andriacchi; David A. Sugar

1998-01-01

223

Automatic gait characterization for a mobility assistance system  

Microsoft Academic Search

This paper addresses gait analysis for a mobility assistance robot designed for the elderly people. Six patients and ten healthy peoples were invited to be part of our first pilot experiment. We designed two experiments so as to firstly detect gait parameters and secondly to identify a change of speed. For the first trial, we compared the temporal-distance parameters of

Cong Zong; Mohamed Chetouani; Adriana Tapus

2010-01-01

224

Gait Regulation and Feedback on a Robotic Climbing Hexapod  

Microsoft Academic Search

This paper proposes a novel method of applying feedback control for legged robots, by directly modifying pa- rameters of a robot's gait pattern. Gaits are a popular means of producing stable locomotion for legged robots, through the use of cyclic feedforward motion patterns, while requiring little to no sensory information. We are interested in incorporating feedback with these systems, and

G. Clark Haynes; Alfred A. Rizzi

2006-01-01

225

On the stability properties of hexapod tripod gait  

Microsoft Academic Search

Hexapod tripod gaits for straight-line motion and crab walking are derived. Mathematical relations that express the stability margin, the stride length, and the duty factor are formulated for straight-line motion and for crab walking, respectively. The derived results provide tripod gaits of the hexapond for walking with a prescribed stability margin either over perfect terrain or constant slope terrain

T.-T. Lee; C.-M. Liao; T. K. Chen

1988-01-01

226

EVOLVING HEXAPOD GAITS USING A CYCLIC GENETIC ALGORITHM  

E-print Network

EVOLVING HEXAPOD GAITS USING A CYCLIC GENETIC ALGORITHM GARY B. PARKER, DAVID W. BRAUN, AND INGO is an integral part of a legged robot control. Hexapod gaits require the coordination of the simultaneous. KEYWORDS: genetic, cyclic, robot, hexapod, control. INTRODUCTION Autonomous hexapod robots can be useful

Parker, Gary B.

227

Fitness Biasing Produce Adaptive Gaits for Hexapod Robots  

E-print Network

Fitness Biasing Produce Adaptive Gaits for Hexapod Robots Gary Parker Computer Science Connecticut in an earlier work an effective learning cycles a hexapod robot. learning system capable of adapting to changes produce gaits hexapod robots difficult problem. particularly challenging if wants programs altered adapt

Parker, Gary B.

228

EVOLVING HEXAPOD GAITS USING A CYCLIC GENETIC ALGORITHM  

Microsoft Academic Search

Gait generation is an integral part of a legged robot control. Hexapod gaits require the coordination of the simultaneous movement of all six legs in a cycle of activations. The problem is compounded when working with actual robots due to the variability in their capabilities. A learning algorithm that can optimize with the differences between and within robots would greatly

GARY B. PARKER; DAVID W. BRAUN; INGO CYLIAX

1997-01-01

229

Gait learning method for stable motion using quadrupedal robot  

Microsoft Academic Search

In the field of pet robots and robot-assisted therapy (RAT), characterization of animal motion is important for the development of robots resembling various animals. This paper presents a method for the generation of animal gait in quadrupedal robots. In this study, we employed AIBO as an experimental quadrupedal robot and generated the gait of the robot on the basis of

Hidekazu Suzuki; Hitoshi Nishi; Seiya Tsuchiya

2010-01-01

230

Using Causal Reasoning in Gait Analysis 1 David E. Hirsch *  

E-print Network

and Computer Science Massachusetts Institute of Technology Sheldon R. Simon Department of Surgery The Ohio (Hirsch, Simon, and Szolovits) at MIT and Harvard, relies exclusively on experiential domain models. Dr by the same three people, is primarily based on a qualitative causal model of gait. Dr. Gait­2 overcame many

Szolovits, Peter

231

Modeling and Gait Design of a 4Tetrahedron Walker Robot  

Microsoft Academic Search

This work describes the use of a simulating walking robot to model a tetrahedron walker robot. As a contribution to the gait generation and motion control of the tetrahedron walker robots, a concept has been formulated to implement in the case of choreographic designed gaits.

M. Abrahantes; D. Littio; A. Silver; L. Wendt

2008-01-01

232

Gait Design and Modeling of a 12Tetrahedron Walker Robot  

Microsoft Academic Search

This work describes the use of a simulating walking robot to model the tetrahedron walker robots being developed at NASA\\/Goddard Space Flight Center. As a contribution to the gait generation and motion control of the tetrahedron walker robots, a concept has been formulated to implement in the case of choreographic designed gaits. This work is part of the contribution of

M. Abrahantes; A. Silver; L. Wendt

2007-01-01

233

Gait Recognition at a Distance Based on Energy Deviation Image  

Microsoft Academic Search

Silhouettes extracted from the videos collected with complex background at a relatively far distance are generally of low quality. Gait Energy Image (GEI) has been reported as a good feature robust to silhouette errors and image noise, but it ignores some gait motion information. This paper proposes to generate energy deviation image (EDI) based on the differences between the GEI

Qinyong Ma; Shenkang Wang; Dongdong Nie; Jianfeng Qiu

2007-01-01

234

Adaptive impedance control of a robotic orthosis for gait rehabilitation.  

PubMed

Intervention of robotic devices in the field of physical gait therapy can help in providing repetitive, systematic, and economically viable training sessions. Interactive or assist-as-needed (AAN) gait training encourages patient voluntary participation in the robotic gait training process which may aid in rapid motor function recovery. In this paper, a lightweight robotic gait training orthosis with two actuated and four passive degrees of freedom (DOFs) is proposed. The actuated DOFs were powered by pneumatic muscle actuators. An AAN gait training paradigm based on adaptive impedance control was developed to provide interactive robotic gait training. The proposed adaptive impedance control scheme adapts the robotic assistance according to the disability level and voluntary participation of human subjects. The robotic orthosis was operated in two gait training modes, namely, inactive mode and active mode, to evaluate the performance of the proposed control scheme. The adaptive impedance control scheme was evaluated on ten neurologically intact subjects. The experimental results demonstrate that an increase in voluntary participation of human subjects resulted in a decrease of the robotic assistance and vice versa. Further clinical evaluations with neurologically impaired subjects are required to establish the therapeutic efficacy of the adaptive-impedance-control-based AAN gait training strategy. PMID:23193241

Hussain, Shahid; Xie, Sheng Q; Jamwal, Prashant K

2013-06-01

235

A continuous-wave (CW) radar for gait analysis  

Microsoft Academic Search

A fully coherent, continuous-wave (CW) radar operating near 10.5 GHz has been developed to record the radar signature corresponding to the walking human gait. The received signal is the sum of Doppler shifted signals reflected from the various parts of the moving body. Since the legs, arms, and torso all move at different relative velocities throughout the gait cycle, the

Jonathan L. Geisheimer; William S. Marshall; Eugene Greneker

2001-01-01

236

Optimality Principles for Model-Based Prediction of Human Gait  

PubMed Central

Although humans have a large repertoire of potential movements, gait patterns tend to be stereotypical and appear to be selected according to optimality principles such as minimal energy. When applied to dynamic musculoskeletal models such optimality principles might be used to predict how a patient’s gait adapts to mechanical interventions such as prosthetic devices or surgery. In this paper we study the effects of different performance criteria on predicted gait patterns using a 2D musculoskeletal model. The associated optimal control problem for a family of different cost functions was solved utilizing the direct collocation method. It was found that fatigue-like cost functions produced realistic gait, with stance phase knee flexion, as opposed to energy-related cost functions which avoided knee flexion during the stance phase. We conclude that fatigue minimization may be one of the primary optimality principles governing human gait. PMID:20074736

Ackermann, Marko; van den Bogert, Antonie J.

2010-01-01

237

Abnormal joint torque patterns exhibited by chronic stroke subjects while walking with a prescribed physiological gait pattern  

PubMed Central

Background It is well documented that individuals with chronic stroke often exhibit considerable gait impairments that significantly impact their quality of life. While stroke subjects often walk asymmetrically, we sought to investigate whether prescribing near normal physiological gait patterns with the use of the Lokomat robotic gait-orthosis could help ameliorate asymmetries in gait, specifically, promote similar ankle, knee, and hip joint torques in both lower extremities. We hypothesized that hemiparetic stroke subjects would demonstrate significant differences in total joint torques in both the frontal and sagittal planes compared to non-disabled subjects despite walking under normal gait kinematic trajectories. Methods A motion analysis system was used to track the kinematic patterns of the pelvis and legs of 10 chronic hemiparetic stroke subjects and 5 age matched controls as they walked in the Lokomat. The subject's legs were attached to the Lokomat using instrumented shank and thigh cuffs while instrumented footlifters were applied to the impaired foot of stroke subjects to aid with foot clearance during swing. With minimal body-weight support, subjects walked at 2.5 km/hr on an instrumented treadmill capable of measuring ground reaction forces. Through a custom inverse dynamics model, the ankle, knee, and hip joint torques were calculated in both the frontal and sagittal planes. A single factor ANOVA was used to investigate differences in joint torques between control, unimpaired, and impaired legs at various points in the gait cycle. Results While the kinematic patterns of the stroke subjects were quite similar to those of the control subjects, the kinetic patterns were very different. During stance phase, the unimpaired limb of stroke subjects produced greater hip extension and knee flexion torques than the control group. At pre-swing, stroke subjects inappropriately extended their impaired knee, while during swing they tended to abduct their impaired leg, both being typical abnormal torque synergy patterns common to stroke gait. Conclusion Despite the Lokomat guiding stroke subjects through physiologically symmetric kinematic gait patterns, abnormal asymmetric joint torque patterns are still generated. These differences from the control group are characteristic of the hip hike and circumduction strategy employed by stroke subjects. PMID:18761735

Neckel, Nathan D; Blonien, Natalie; Nichols, Diane; Hidler, Joseph

2008-01-01

238

A Novel Approach to Quantify Time Series Differences of Gait Data Using Attractor Attributes  

PubMed Central

In this paper we introduce a new method to expressly use live/corporeal data in quantifying differences of time series data with an underlying limit cycle attractor; and apply it using an example of gait data. Our intention is to identify gait pattern differences between diverse situations and classify them on group and individual subject levels. First we approximated the limit cycle attractors, from which three measures were calculated: ?M amounts to the difference between two attractors (a measure for the differences of two movements), ?D computes the difference between the two associated deviations of the state vector away from the attractor (a measure for the change in movement variation), and ?F, a combination of the previous two, is an index of the change. As an application we quantified these measures for walking on a treadmill under three different conditions: normal walking, dual task walking, and walking with additional weights at the ankle. The new method was able to successfully differentiate between the three walking conditions. Day to day repeatability, studied with repeated trials approximately one week apart, indicated excellent reliability for ?M (ICCave > 0.73 with no differences across days; p > 0.05) and good reliability for ?D (ICCave ?=? 0.414 to 0.610 with no differences across days; p > 0.05). Based on the ability to detect differences in varying gait conditions and the good repeatability of the measures across days, the new method is recommended as an alternative to expensive and time consuming techniques of gait classification assessment. In particular, the new method is an easy to use diagnostic tool to quantify clinical changes in neurological patients. PMID:23951252

Vieten, Manfred M.; Sehle, Aida; Jensen, Randall L.

2013-01-01

239

A novel shear reduction insole effect on the thermal response to walking stress, balance, and gait.  

PubMed

Shear stresses have been implicated in the formation of diabetes-related foot ulcers. The aim of this study was to evaluate the effect of a novel shear-reducing insole on the thermal response to walking, balance, and gait. Twenty-seven diabetes peripheral neuropathy patients were enrolled and asked to take 200 steps in both intervention and standard insoles. Thermal foot images of the feet were taken at baseline (1) following a 5-minute temperature acclimatization and (2) after walking. Testing order was randomized, and a 5-minute washout period was used between testing each insole condition. Sudomotor function was also assessed. Gait and balance were measured under single and dual task conditions using a validated body worn sensor system. The mean age was 65.1 years, height was 67.3 inches, weight was 218 pounds, and body mass index was 33.9, 48% were female, and 82% had type 2 diabetes. After walking in both insole conditions, foot temperatures increased significantly in standard insoles. The intervention insole significantly reduced forefoot and midfoot temperature increases (64.1%, P = .008; 48%, P = .046) compared to standard insoles. There were significant negative correlations with sudomotor function and baseline temperatures (r = .53-.57). The intervention demonstrated 10.4% less gait initiation double support time compared to standard insoles (P = .05). There were no differences in static balance measures. We found significantly lower forefoot and midfoot temperature increases following walking with shear-reducing insoles compared to standard insoles. We also found improvements in gait. These findings merit future study for the prevention of foot ulcer. PMID:25107709

Wrobel, James S; Ammanath, Peethambaran; Le, Tima; Luring, Christopher; Wensman, Jeffrey; Grewal, Gurtej S; Najafi, Bijan; Pop-Busui, Rodica

2014-11-01

240

Imaging: what can it tell us about parkinsonian gait?  

PubMed Central

Functional neuroimaging has provided new tools to study cerebral gait control in Parkinson disease (PD). First, imaging of blood flow functions has identified a supraspinal locomotor network that includes the (frontal) cortex, basal ganglia, brainstem tegmentum and the cerebellum. These studies emphasize also the cognitive and attentional dependency of gait in PD. Furthermore, gait in PD and related syndromes like progressive supranuclear palsy may be associated with dysfunction of the indirect, modulatory prefrontal–subthalamic–pedunculopontine loop of locomotor control. The direct, stereotyped locomotor loop from the primary motor cortex to the spinal cord with rhythmic cerebellar input appears preserved and may contribute to the unflexible gait pattern in parkinsonian gait. Second, neurotransmitter and proteinopathy imaging studies are beginning to unravel novel mechanisms of parkinsonian gait and postural disturbances. Dopamine displacement imaging studies have shown evidence for a mesofrontal dopaminergic shift from a depleted striatum in parkinsonian gait. This may place additional burden on other brain systems mediating attention functions to perform previously automatic motor tasks. For example, our preliminary cholinergic imaging studies suggest significant slowing of gait speed when additional forebrain cholinergic denervation occurs in PD. Cholinergic denervation of the pedunculopontine nucleus and its thalamic projections have been associated with falls and impaired postural control. Deposition of ?-amyloid may represent another non-dopaminergic correlate of gait disturbance in PD. These findings illustrate the emergence of dopamine non-responsive gait problems to reflect the transition from a predominantly hypodopaminergic disorder to a multisystem neurodegenerative disorder involving non-dopaminergic locomotor network structures and pathologies. PMID:24132837

Bohnen, Nicolaas I.; Jahn, Klaus

2013-01-01

241

Optimal Synchronizability of Bearings  

E-print Network

Bearings are mechanical dissipative systems that, when perturbed, relax toward a synchronized (bearing) state. Here we find that bearings can be perceived as physical realizations of complex networks of oscillators with ...

Seybold, Hansjorg

242

Bearing Remover And Presser  

NASA Technical Reports Server (NTRS)

Document describes simple bearing-servicing tool consisting of only three parts capable of removing and replacing rotary bearing within race. Threaded drive operates between guide and pressure plate for dislodging bearing from race.

Boyce, Rex A.

1995-01-01

243

ES and H-compatible lubrication for duplex bearings  

SciTech Connect

Two ES and H-compatible lubricants (environment, safety, and health) for duplex bearing applications and one hybrid material duplex bearing were evaluated and compared against duplex bearings with trichlorotrifluoroethane (Freon) deposition of low molecular weight polytetrafluoroethylene (PTFE) bearing lubricant extracted from Vydax{trademark}. Vydax is a product manufactured by DuPont consisting of various molecular weights of PTFE suspended in trichlorotrifluoroethane (Freon), which is an ozone-depleting solvent. Vydax has been used as a bearing lubricant in strong link mechanisms since 1974. Hybrid duplex bearings with silicon nitride balls and molded glass-nylon-Teflon retainers, duplex bearings lubricated with sputtered MoS{sub 2} on races and retainers, and duplex bearings lubricated with electrophoretic deposited MoS{sub 2} were evaluated. Bearings with electrophoretic deposited MoS{sub 2} performed as well as bearings with Freon deposition of PTFE from Freon-based Vydax. Hybrid bearings with silicon nitride balls performed worse than bearings lubricated with Vydax, but their performance would still be acceptable for most applications. Bearings lubricated with sputtered MoS{sub 2} on the races and retainers had varying amounts of film on the bearings. This affected the performance of the bearings. Bearings with a uniform coating performed to acceptable levels, but bearings with no visible MoS{sub 2} on the races and retainers did not perform as well as bearings with the other coatings. Unless process controls are incorporated in the sputtering process or the bearings are screened, they do not appear to be acceptable for duplex bearing applications.

Steinhoff, R.G.

1997-10-01

244

Gait Evolution for a Hexapod Robot Karen Larochelle, Sarah Dashnaw, and Gary Parker  

E-print Network

Gait Evolution for a Hexapod Robot Karen Larochelle, Sarah Dashnaw, and Gary Parker Computer (simultaneous commands to the leg actua- tors) for hexapod gaits has been done using Cyclic Ge- netic Algorithms with measured rates for all possible leg movements to generate gaits for a hexapod robot. These gaits

Parker, Gary B.

245

The Effects of Using a Greedy Factor in Hexapod Gait Learning  

E-print Network

The Effects of Using a Greedy Factor in Hexapod Gait Learning Gary B. Parker and William T. Tarimo of this study are tested on a Cyclic Genetic Algorithm (CGA) used for learning gaits for a hexapod servo in the desired optimal gaits. Keywords- Genetic Algorithm; Cyclic Control; Hexapod; Greedy Selection; Gait

Parker, Gary B.

246

Increasing Biped Gait Stability via Phase Resetting Mechanism Prof. Taishin Nomura  

E-print Network

on the gait phase at the perturbation and could play an important role for preventing the walker from a fall were applied using push- impacts by a pendulum-like hammer to the back of the robot during gait of falling against the perturbation during the three-dimensional robot gait. A parallelism with human gait

Sandini, Giulio

247

Neural-based human's abnormal gait detection using Force Sensitive Resistors  

Microsoft Academic Search

Abnormal gait leads to falling which can cause of human's injury. Normally human has resembled gait cycle between walking. But if human has falling or abnormal walking that gait cycle is not resemble the normal walking. The walking gait can calculate the locus of the Zero Moment Point (ZMP) and the ZMP can be estimated by the signal from low-cost

J. Pawin; T. Khaorapapong; S. Chawalit

2011-01-01

248

The spectrum of preclinical gait disorders in early Parkinson's disease: subclinical gait abnormalities and compensatory mechanisms revealed with dual tasking.  

PubMed

Patients with early Parkinson's disease (PD) may not complain of gait difficulties but subtle gait abnormalities may be revealed as part of a "preclinical gait syndrome" when they are challenged by dual tasks. 21 early PD patients (n = 21, mean age 63.5 years, H&Y 1.62, disease duration <5 years, mean UPDRS-III 7.7) who did not have gait complaints were as compared to age- and gender-matched healthy controls (n = 21). Memory function was not different between the two groups. Under normal walking conditions, there were no significant differences in gait parameters between the patients and the control group. In both groups, normalized gait velocity decreased in response to dual tasking in a parallel fashion (p < 0.001). Similarly, gait variability increased in both groups with dual tasking although not statistically significant. In PD patients, the performance of an additional task resulted in an increased number of cadences (p = 0.04), a reduction in swing time (p = 0.02) and cycle time (p = 0.04) compared with the control group but there was no significant reduction in normalized velocity. Stride width also increased in the PD patients. The addition of a cognitive task may affect certain aspects of gait and is able to elicit subclinical deficits in early PD patients. In an attempt to maintain velocity, early PD patients develop compensatory mechanisms by increasing cadence and decreasing swing time and cycle time. Increased step width helps support balance, and prevents going beyond the base-of-support which may predispose to unsteadiness and falls. We propose that these findings occur as part of a spectrum of a "preclinical gait syndrome" and longitudinal studies are needed to assess the predictive values of these early markers of gait deficits. PMID:23784344

Panyakaew, Pattamon; Bhidayasiri, Roongroj

2013-12-01

249

Lubricant replacement in rolling element bearings for weapon surety devices  

SciTech Connect

Stronglink switches are a weapon surety device that is critical to the nuclear safety theme in modem nuclear weapons. These stronglink switches use rolling element bearings which contain a lubricant consisting of low molecular weight polytetrafluoroethylene (PTFE) fragments. Ozone-depleting solvents are used in both the manufacture and application of this lubricant. An alternate bearing lubrication for stronglink switches is needed that will provide long-term chemical stability, low migration and consistent performance. Candidates that were evaluated include bearings with sputtered MoS{sub 2} on the races and retainers, bearings with TiC-coated balls, and bearings with Si{sub 3}N{sub 4} balls and steel races. These candidates were compared to the lubricants currently used which are bearings lubricated with PTFE fragments of low molecular weight in a fluorocarbon solvent. The candidates were also compared to bearings lubricated with a diester oil which is representative of bearing lubricants used in industrial applications. Evaluation consisted of cycling preloaded bearings and subjecting them to 23 gRMS random vibration. All of the candidates are viable substitutes for low load application where bearing preload is approximately 1 pound. For high load applications where the bearing preload is approximately 10 pounds, bearings with sputtered MoS{sub 2} on the races and retainers appear to be the best substitutes. Bearings with TiC-coated balls also appear to be a viable candidate but these bearings did not perform as well as the sputtered MoS{sub 2}.

Steinhoff, R.; Dugger, M.T.; Varga, K.S. [Sandia National Laboratories, Albuquerque, NM (United States)

1996-05-01

250

Effects of load carriage and fatigue on gait characteristics.  

PubMed

The objective of this study was to determine the main and interactive effects of load carriage and fatigue on gait characteristics. Twelve young male participants were recruited in this study. Fatiguing protocol involved a running exercise, and fatigue was considered to be induced when the participants first gave an RPE rating at or above 17. Gait data were collected when the participants walked on a medical treadmill at their self-selected comfortable speed, both before and right after the fatiguing exercise. Different back-carrying loads (i.e. 0, 7.5, and 15 kg) were applied separately to the participants during the walking trials. Gait variability measures and kinematic measures were used to quantify gait characteristics. The results showed that gait width variability, hip range of motion, and trunk range of motion increased with fatigue and with the application of the heavy load. These findings suggest that both fatigue and load carriage compromise gait. Findings from this study can help better understand how fatigue and load carriage affect gait, and further aid in developing interventions that are able to minimize fall risks especially with the application of fatigue and/or external load. PMID:21397234

Qu, Xingda; Yeo, Joo Chuan

2011-04-29

251

Criteria of gait asymmetry in patients with hip osteoarthritis.  

PubMed

Gait symmetry is often a goal for physiotherapy in patients with hip osteoarthritis and after total hip replacement. However, there is no agreement on criteria for pathological gait asymmetry. In this study we investigated discriminative abilities of trunk and footfall gait symmetry measures, and thereafter assessed whether a 10% cutoff value is valid as a general criterion of pathological gait asymmetry across measures. Anteroposterior, vertical, and mediolateral trunk symmetry, single support, and step length symmetry were obtained simultaneously by trunk accelerometry and an electronic walkway in 37 patients with end-stage hip osteoarthritis and 56 controls. Subjects walked six times along a 7-meter walkway at slow, preferred, and fast speed, before data were normalized for gait velocity. Anteroposterior, vertical, and single support symmetry measures showed best discriminating abilities. The general 10% criterion of gait asymmetry and optimal cutoff criteria calculated for each symmetry measure showed approximately equal total classification ability. However, the optimal cutoff criteria classified a high number of controls as having pathological gait asymmetry. The general criterion of 10% is valid with high total classification ability, does not classify asymmetry in able-bodied subjects as pathological, and is feasible for use on individual patients in the clinic as well as in research. PMID:21722001

Hodt-Billington, Caroline; Helbostad, Jorunn L; Vervaat, Willemijn; Rognsvåg, Turid; Moe-Nilssen, Rolf

2012-02-01

252

Design and test of a magnetic thrust bearing  

NASA Technical Reports Server (NTRS)

A magnetic thrust bearing can be employed to take thrust loads in rotating machinery. The design and construction of a prototype magnetic thrust bearing for a high load per weight application is described. The theory for the bearing is developed. Fixtures were designed and the bearing was tested for load capacity using a universal testing machine. Various shims were employed to have known gap thicknesses. A comparison of the theory and measured results is presented.

Allaire, P. E.; Mikula, A.; Banerjee, B.; Lewis, D. W.; Imlach, J.

1993-01-01

253

Gait variability and basal ganglia disorders: stride-to-stride variations of gait cycle timing in Parkinson's disease and Huntington's disease  

NASA Technical Reports Server (NTRS)

The basal ganglia are thought to play an important role in regulating motor programs involved in gait and in the fluidity and sequencing of movement. We postulated that the ability to maintain a steady gait, with low stride-to-stride variability of gait cycle timing and its subphases, would be diminished with both Parkinson's disease (PD) and Huntington's disease (HD). To test this hypothesis, we obtained quantitative measures of stride-to-stride variability of gait cycle timing in subjects with PD (n = 15), HD (n = 20), and disease-free controls (n = 16). All measures of gait variability were significantly increased in PD and HD. In subjects with PD and HD, gait variability measures were two and three times that observed in control subjects, respectively. The degree of gait variability correlated with disease severity. In contrast, gait speed was significantly lower in PD, but not in HD, and average gait cycle duration and the time spent in many subphases of the gait cycle were similar in control subjects, HD subjects, and PD subjects. These findings are consistent with a differential control of gait variability, speed, and average gait cycle timing that may have implications for understanding the role of the basal ganglia in locomotor control and for quantitatively assessing gait in clinical settings.

Hausdorff, J. M.; Cudkowicz, M. E.; Firtion, R.; Wei, J. Y.; Goldberger, A. L.

1998-01-01

254

Improvement of Freezing of Gait in Patients with Parkinson's Disease by Imagining Bicycling  

PubMed Central

Freezing of gait (FOG) is one of the factors that reduce the quality of life in patients with Parkinson's disease (PD). Imagining bicycling before gait start provided improvement in FOG in 2 PD patients. Imagining and mimicking bicycling after the initiation of gait allowed the rhythmic gait to continue without interruption. We suggest that imagining and mimicking bicycling, which are nonexternal cues, could serve as a helpful therapeutic approach for the intractable freezing and interruption of gait of PD patients. PMID:24761145

Kikuchi, Akio; Baba, Toru; Hasegawa, Takafumi; Sugeno, Naoto; Konno, Masatoshi; Miura, Emiko; Oshima, Ryuji; Aoki, Masashi; Takeda, Atsushi

2014-01-01

255

Stepping strategies for regulating gait adaptability and stability.  

PubMed

Besides a stable gait pattern, gait in daily life requires the capability to adapt this pattern in response to environmental conditions. The purpose of this study was to elucidate the anticipatory strategies used by able-bodied people to attain an adaptive gait pattern, and how these strategies interact with strategies used to maintain gait stability. Ten healthy subjects walked in a Computer Assisted Rehabilitation ENvironment (CAREN). To provoke an adaptive gait pattern, subjects had to hit virtual targets, with markers guided by their knees, while walking on a self-paced treadmill. The effects of walking with and without this task on walking speed, step length, step frequency, step width and the margins of stability (MoS) were assessed. Furthermore, these trials were performed with and without additional continuous ML platform translations. When an adaptive gait pattern was required, subjects decreased step length (p<0.01), tended to increase step width (p=0.074), and decreased walking speed while maintaining similar step frequency compared to unconstrained walking. These adaptations resulted in the preservation of equal MoS between trials, despite the disturbing influence of the gait adaptability task. When the gait adaptability task was combined with the balance perturbation subjects further decreased step length, as evidenced by a significant interaction between both manipulations (p=0.012). In conclusion, able-bodied people reduce step length and increase step width during walking conditions requiring a high level of both stability and adaptability. Although an increase in step frequency has previously been found to enhance stability, a faster movement, which would coincide with a higher step frequency, hampers accuracy and may consequently limit gait adaptability. PMID:23332822

Hak, Laura; Houdijk, Han; Steenbrink, Frans; Mert, Agali; van der Wurff, Peter; Beek, Peter J; van Dieën, Jaap H

2013-03-15

256

Medication improves balance and complex gait performance in Parkinson disease.  

PubMed

Gait and balance impairments in people with Parkinson disease (PD) may lead to falls and serious injuries. Therefore, it is critical to improve our understanding of the nature of these impairments, including how they respond to prescribed anti-Parkinson medication. This is particularly important for complex balance and gait tasks that may be associated with falls. We evaluated motor function, functional balance, and gait performance during various gait tasks in 22 people with PD OFF and ON medication (PD OFF, PD ON) and 20 healthy older adults. Although MDS-UPDRS-III score, Berg Balance Scale, Mini-Balance Evaluations Systems test, and Timed-Up-and-Go improved in PD with medication, impairments persisted in all measures on medication, compared to controls. Dual task Timed-Up-and-Go did not improve with medication, and PD ON required more time than controls. Gait velocity and stride length improved similarly with medication in PD across forward, fast, backward, dual task forward, and dual task backward gait tasks. Cadence did not change with medication, nor did it differ between PD ON and controls. Velocity and stride length were reduced in PD ON compared to controls. Velocity reductions in PD ON during fast gait were cadence-mediated, while velocity reductions in backward gait were stride length-mediated. Our results suggest functional balance improves with medication in PD and gait performance improves with medication, regardless of task complexity. Remaining impairments on medication highlight the need to examine additional therapeutic options for individuals with PD to reduce the risk of falls. PMID:22418585

McNeely, Marie E; Duncan, Ryan P; Earhart, Gammon M

2012-05-01

257

Adaptive control of center of mass (global) motion and its joint (local) origin in gait.  

PubMed

Dynamic gait stability can be quantified by the relationship of the motion state (i.e. the position and velocity) between the body center of mass (COM) and its base of support (BOS). Humans learn how to adaptively control stability by regulating the absolute COM motion state (i.e. its position and velocity) and/or by controlling the BOS (through stepping) in a predictable manner, or by doing both simultaneously following an external perturbation that disrupts their regular relationship. Post repeated-slip perturbation training, for instance, older adults learned to forward shift their COM position while walking with a reduced step length, hence reduced their likelihood of slip-induced falls. How and to what extent each individual joint influences such adaptive alterations is mostly unknown. A three-dimensional individualized human kinematic model was established. Based on the human model, sensitivity analysis was used to systematically quantify the influence of each lower limb joint on the COM position relative to the BOS and the step length during gait. It was found that the leading foot had the greatest effect on regulating the COM position relative to the BOS; and both hips bear the most influence on the step length. These findings could guide cost-effective but efficient fall-reduction training paradigm among older population. PMID:24998991

Yang, Feng; Pai, Yi-Chung

2014-08-22

258

Getting Your Bearings  

NSDL National Science Digital Library

In this activity, learners explore the concept of friction and how ball bearings reduce friction. Learners investigate different uses for ball bearings, how the design has changed over time to incorporate roller bearings, test friction using marbles, and identify the use of ball bearings in everyday items.

Ieee

2013-08-30

259

Bearings for Your Whirligig  

NSDL National Science Digital Library

Experiment with friction and make bearings for a whirligig! This activity is a nice introduction to friction and bearings and demonstrates why bearings are useful for spinning. A related video show Vollis Simpson, an artist who creates kinetic sculptures and whirligigs, explain how he uses bearings in all of his spinning pieces so that they move smoothly.

Minnesota, Science M.

1995-01-01

260

Passive magnetic bearing configurations  

DOEpatents

A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

Post, Richard F. (Walnut Creek, CA)

2011-01-25

261

Abstract--Inspired by the observation that the cockroach changes the tripod gait to other gait to cross the step, we report  

E-print Network

to cross the step, we report on the design of the step crossing gait in a RHex-style hexapod robot which side, gait design of the hexapod robots in simulation is reported. For example, step and pulse climbing

Lin, Pei-Chun

262

Introduction to ball bearings  

NASA Technical Reports Server (NTRS)

The purpose of a ball bearing is to provide a relative positioning and rotational freedom while transmitting a load between two structures, usually a shaft and a housing. For high rotational speeds (e.g., in gyroscope ball bearings) the purpose can be expanded to include rotational freedom with practically no wear in the bearing. This condition can be achieved by separating the bearing parts with a coherent film of fluid known as an elastohydrodynamic film. This film can be maintained not only when the bearing carries the load on a shaft, but also when the bearing is preloaded to position the shaft to within micro- or nano-inch accuracy and stability. Background information on ball bearings is provided, different types of ball bearings and their geometry and kinematics are defined, bearing materials, manufacturing processes, and separators are discussed. It is assumed, for the purposes of analysis, that the bearing carries no load.

Hamrock, B. J.; Dowson, D.

1981-01-01

263

Concurrent prediction of muscle and tibiofemoral contact forces during treadmill gait.  

PubMed

Detailed knowledge of knee kinematics and dynamic loading is essential for improving the design and outcomes of surgical procedures, tissue engineering applications, prosthetics design, and rehabilitation. This study used publicly available data provided by the "Grand Challenge Competition to Predict in-vivo Knee Loads" for the 2013 American Society of Mechanical Engineers Summer Bioengineering Conference (Fregly et al., 2012, "Grand Challenge Competition to Predict in vivo Knee Loads," J. Orthop. Res., 30, pp. 503-513) to develop a full body, musculoskeletal model with subject specific right leg geometries that can concurrently predict muscle forces, ligament forces, and knee and ground contact forces. The model includes representation of foot/floor interactions and predicted tibiofemoral joint loads were compared to measured tibial loads for two different cycles of treadmill gait. The model used anthropometric data (height and weight) to scale the joint center locations and mass properties of a generic model and then used subject bone geometries to more accurately position the hip and ankle. The musculoskeletal model included 44 muscles on the right leg, and subject specific geometries were used to create a 12 degrees-of-freedom anatomical right knee that included both patellofemoral and tibiofemoral articulations. Tibiofemoral motion was constrained by deformable contacts defined between the tibial insert and femoral component geometries and by ligaments. Patellofemoral motion was constrained by contact between the patellar button and femoral component geometries and the patellar tendon. Shoe geometries were added to the feet, and shoe motion was constrained by contact between three shoe segments per foot and the treadmill surface. Six-axis springs constrained motion between the feet and shoe segments. Experimental motion capture data provided input to an inverse kinematics stage, and the final forward dynamics simulations tracked joint angle errors for the left leg and upper body and tracked muscle length errors for the right leg. The one cycle RMS errors between the predicted and measured tibia contact were 178?N and 168?N for the medial and lateral sides for the first gait cycle and 209?N and 228?N for the medial and lateral sides for the faster second gait cycle. One cycle RMS errors between predicted and measured ground reaction forces were 12?N, 13?N, and 65?N in the anterior-posterior, medial-lateral, and vertical directions for the first gait cycle and 43?N, 15?N, and 96?N in the anterior-posterior, medial-lateral, and vertical directions for the second gait cycle. PMID:24389997

Guess, Trent M; Stylianou, Antonis P; Kia, Mohammad

2014-02-01

264

On using gait in forensic biometrics.  

PubMed

Given the continuing advances in gait biometrics, it appears prudent to investigate the translation of these techniques for forensic use. We address the question as to the confidence that might be given between any two such measurements. We use the locations of ankle, knee, and hip to derive a measure of the match between walking subjects in image sequences. The Instantaneous Posture Match algorithm, using Harr templates, kinematics, and anthropomorphic knowledge is used to determine their location. This is demonstrated using real CCTV recorded at Gatwick International Airport, laboratory images from the multiview CASIA-B data set, and an example of real scene of crime video. To access the measurement confidence, we study the mean intra- and inter-match scores as a function of database size. These measures converge to constant and separate values, indicating that the match measure derived from individual comparisons is considerably smaller than the average match measure from a population. PMID:21554307

Bouchrika, Imed; Goffredo, Michaela; Carter, John; Nixon, Mark

2011-07-01

265

High efficiency magnetic bearings  

NASA Technical Reports Server (NTRS)

Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, parameters needed to describe the bearing are explained. Then, methods developed for the design and testing of magnetic bearings are summarized. Finally, a new magnetic bearing which allows active torque control in the off axes directions is discussed.

Studer, Philip A.; Jayaraman, Chaitanya P.; Anand, Davinder K.; Kirk, James A.

1993-01-01

266

High efficiency magnetic bearings  

NASA Astrophysics Data System (ADS)

Research activities concerning high efficiency permanent magnet plus electromagnet (PM/EM) pancake magnetic bearings at the University of Maryland are reported. A description of the construction and working of the magnetic bearing is provided. Next, parameters needed to describe the bearing are explained. Then, methods developed for the design and testing of magnetic bearings are summarized. Finally, a new magnetic bearing which allows active torque control in the off axes directions is discussed.

Studer, Philip A.; Jayaraman, Chaitanya P.; Anand, Davinder K.; Kirk, James A.

267

A dynamic cadaver model of the stance phase of gait: performance characteristics and kinetic validation.  

PubMed

OBJECTIVE: This study was undertaken to evaluate the performance of a new dynamic laboratory model of the stance phase of gait. DESIGN: Five cadaver feet were repetitively tested in the apparatus. BACKGROUND: Typical biomechanical investigations of cadaver feet simply place a static load on the tibia. The present system was designed to better simulate the changing in-vivo loading environment of the foot and ankle during gait. METHODS: The device mimics the behavior of the tibia, foot, and ankle from heel-strike to toe-off by reproducing the physiologic actions of five extrinsic foot muscles and physiologic motion at the proximal tibia. To verify its utility, cadaver gait simulations were conducted while measuring applied muscle forces, ground reaction forces, and plantar pressures. RESULTS: Dynamic muscle forces were consistently delivered to within 10% of pre-programmed values. Dynamic measurements of ground reaction forces and plantar pressure were similar to those measured in healthy human subjects. Peak vertical (y), foreaft (x) and medio-lateral (z) forces were 110, 18, and 4% of body weight respectively. Compressive force in the tibial shaft reached 410% of body weight. RELEVANCE: Cadaver studies have greatly enhanced our understanding of normal and pathologic foot function, but are often limited by over-simplified loading conditions. The apparatus presented here accurately reproduces the in-vivo loading environment and provides a powerful investigational tool for the study of foot and ankle function. With this device, musculoskeletal structures can be examined in detail under biomechanical conditions similar to those they experience in life. PMID:11415817

Sharkey, Neil A.; Hamel, Andrew J.

1998-09-01

268

MODELING AND SIMULATION OF NORMAL AND PATHOLOGICAL GAIT  

E-print Network

and Scott L. Delp The diagnosis and treatment of gait abnormalities in children with cerebral palsy is challenging. A combination of several factors, including muscle spasticity, muscle weak- ness, bony

Delp, Scott

269

Low Power Shoe Integrated Intelligent Wireless Gait Measurement System  

NASA Astrophysics Data System (ADS)

Gait analysis measurement is a method to assess and identify gait events and the measurements of dynamic, motion and pressure parameters involving the lowest part of the body. This significant analysis is widely used in sports, rehabilitation as well as other health diagnostic towards improving the quality of life. This paper presents a new system empowered by Inertia Measurement Unit (IMU), ultrasonic sensors, piezoceramic sensors array, XBee wireless modules and Arduino processing unit. This research focuses on the design and development of a low power ultra-portable shoe integrated wireless intelligent gait measurement using MEMS and recent microelectronic devices for foot clearance, orientation, error correction, gait events and pressure measurement system. It is developed to be cheap, low power, wireless, real time and suitable for real life in-door and out-door environment.

Wahab, Y.; Mazalan, M.; Bakar, N. A.; Anuar, A. F.; Zainol, M. Z.; Hamzah, F.

2014-04-01

270

Detection of freezing of gait in Parkinson disease: preliminary results.  

PubMed

Freezing of gait (FOG) is a common symptom in Parkinsonism, which affects the gait pattern and is associated to a fall risk. Automatized FOG episode detection would allow systematic assessment of patient state and objective evaluation of the clinical effects of treatments. Techniques have been proposed in the literature to identify FOG episodes based on the frequency properties of inertial sensor signals. Our objective here is to adapt and extend these FOG detectors in order to include other associated gait pattern changes, like festination. The proposed approach is based on a single wireless inertial sensor placed on the patient's lower limbs. The preliminary experimental results show that existing frequency-based freezing detectors are not sufficient to detect all FOG and festination episodes and that the observation of some gait parameters such as stride length and cadence are valuable inputs to anticipate the occurrence of upcoming FOG events. PMID:24740014

Coste, Christine Azevedo; Sijobert, Benoît; Pissard-Gibollet, Roger; Pasquier, Maud; Espiau, Bernard; Geny, Christian

2014-01-01

271

Further results on control of the compass gait biped  

Microsoft Academic Search

This paper continues our investigations into the passivity-based control of the compass gait biped. It was shown in [Spong, M.W., 1999] for the compass gait biped, and in [Spong, M.W., and Bullo, F., 2002] for the general case, that a passive limit cycle for a given constant slope can be made slope invariant via potential energy shaping control. In this

Mark W. Spong; Gagandeep Bhatia

2003-01-01

272

Optimal Gait Synthesis of a Seven-Link Planar Biped  

Microsoft Academic Search

In this paper, we carry out the dynamics-based optimization of sagittal gait cycles of a planar seven-link biped using the Pontryagin maximum principle. Special attention is devoted to the double-support phase of the gait, during which the movement is subjected to severe limiting conditions. In particular, due to the fact that the biped moves as a closed kinematic chain, overactuation

Guy Bessonnet; Stéphane Chessé; Philippe Sardain

2004-01-01

273

Bringing the compass-gait bipedal walker to three dimensions  

Microsoft Academic Search

The planar compass-gait biped has been exten- sively studied in the dynamic walking community, motivated by the gravity-based pendular efficiencies of human walking. These results can be extended to three dimensions using controlled geometric reduction for open-chain robots, by which stable 3- D walking gaits are built from known sagittal-plane limit cycles. We apply this method to the standard and

Robert D. Gregg; Mark W. Spong

2009-01-01

274

Variation in human gait intervals on a treadmill  

E-print Network

VARIATION IN HUMAN GAIT INTERVALS ON A TREADMILL A Thesis by MARK ALAN ABRAMS Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1994 Major... Subject: Bioengineering VARIATION IN HUMAN GAIT INTERVALS ON A TREADMILL A Thesis by Submitted to Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style and content by: Willia A...

Abrams, Mark Alan

2012-06-07

275

A Wearable Acceleration Sensor System for Gait Recognition  

Microsoft Academic Search

This paper addresses the problem of human recognition based on their gait acceleration signal characteristics produced by walking. A portable microprocessor-based data collection device was designed to measure the three-dimensional gait acceleration signals during human walking. The system consists of a tri-axial accelerometer, a MCU, 32 M bytes of RAM, and a data transfer module for data transfer. The device

Liu Rong; Zhou Jianzhong; Liu Ming; Hou Xiangfeng

2007-01-01

276

Analysis of step-to-step and intrastep gait patterns  

E-print Network

Major Subject: Bioengineering ANALYSIS OF STEP-TO-STEP AND INTRASTEP GAIT PATTERNS A Thesis by GYU SUNG LEE Submitted to Texas A8UM University in partial fulidlment of the requirements for the degree of MASTER OF SCIENCE Approved as to style... and content by: W' ' A. yman (Chair of ' e) aid E. Miller (Member) William . Lively (Member) Way (Head of artment) August 1996 Major Subject: Bioengineering ABSTRACT Analysis of Step-to-step and Intrastep Gait Patterns. (August 1996) Gyusung Lee...

Lee, Gyusung

2012-06-07

277

Gait characteristics in people with type 2 diabetes mellitus  

Microsoft Academic Search

Sixteen control subjects and 15 subjects with type 2 diabetes were examined to compare gait characteristics during walking in a linear path and in turns of 0.33 and 0.66 m diameter. Subjects were excluded if there was diminished sensation in the feet or impairment of strength in the legs. This was done to isolate the effect of diabetes gait independent of

Jerrold Petrofsky; Scott Lee; Salameh Bweir

2005-01-01

278

Gait Patterns in Hemiplegic Patients with Equinus Foot Deformity  

PubMed Central

Equinus deformity of the foot is a common feature of hemiplegia, which impairs the gait pattern of patients. The aim of the present study was to explore the role of ankle-foot deformity in gait impairment. A hierarchical cluster analysis was used to classify the gait patterns of 49 chronic hemiplegic patients with equinus deformity of the foot, based on temporal-distance parameters and joint kinematic measures obtained by an innovative protocol for motion assessment in the sagittal, frontal, and transverse planes, synthesized by parametrical analysis. Cluster analysis identified five subgroups of patients with homogenous levels of dysfunction during gait. Specific joint kinematic abnormalities were found, according to the speed of progression in each cluster. Patients with faster walking were those with less ankle-foot complex impairment or with reduced range of motion of ankle-foot complex, that is with a stiff ankle-foot complex. Slow walking was typical of patients with ankle-foot complex instability (i.e., larger motion in all the planes), severe equinus and hip internal rotation pattern, and patients with hip external rotation pattern. Clustering of gait patterns in these patients is helpful for a better understanding of dysfunction during gait and delivering more targeted treatment. PMID:24967417

Manca, M.; Ferraresi, G.; Cosma, M.; Cavazzuti, L.; Morelli, M.; Benedetti, M. G.

2014-01-01

279

User Identification Using Gait Patterns on UbiFloorII  

PubMed Central

This paper presents a system of identifying individuals by their gait patterns. We take into account various distinguishable features that can be extracted from a user’s gait and then divide them into two classes: walking pattern and stepping pattern. The conditions we assume are that our target environments are domestic areas, the number of users is smaller than 10, and all users ambulate with bare feet considering the everyday lifestyle of the Korean home. Under these conditions, we have developed a system that identifies individuals’ gait patterns using our biometric sensor, UbiFloorII. We have created UbiFloorII to collect walking samples and created software modules to extract the user’s gait pattern. To identify the users based on the gait patterns extracted from walking samples over UbiFloorII, we have deployed multilayer perceptron network, a feedforward artificial neural network model. The results show that both walking pattern and stepping pattern extracted from users’ gait over the UbiFloorII are distinguishable enough to identify the users and that fusing two classifiers at the matching score level improves the recognition accuracy. Therefore, our proposed system may provide unobtrusive and automatic user identification methods in ubiquitous computing environments, particularly in domestic areas. PMID:22163758

Yun, Jaeseok

2011-01-01

280

Automatic identification of gait events using an instrumented sock  

PubMed Central

Background Textile-based transducers are an emerging technology in which piezo-resistive properties of materials are used to measure an applied strain. By incorporating these sensors into a sock, this technology offers the potential to detect critical events during the stance phase of the gait cycle. This could prove useful in several applications, such as functional electrical stimulation (FES) systems to assist gait. Methods We investigated the output of a knitted resistive strain sensor during walking and sought to determine the degree of similarity between the sensor output and the ankle angle in the sagittal plane. In addition, we investigated whether it would be possible to predict three key gait events, heel strike, heel lift and toe off, with a relatively straight-forward algorithm. This worked by predicting gait events to occur at fixed time offsets from specific peaks in the sensor signal. Results Our results showed that, for all subjects, the sensor output exhibited the same general characteristics as the ankle joint angle. However, there were large between-subjects differences in the degree of similarity between the two curves. Despite this variability, it was possible to accurately predict gait events using a simple algorithm. This algorithm displayed high levels of trial-to-trial repeatability. Conclusions This study demonstrates the potential of using textile-based transducers in future devices that provide active gait assistance. PMID:21619570

2011-01-01

281

Gait strategy in genetically obese patients: a 7-year follow up.  

PubMed

The aim of this study was to quantitatively evaluate the change in gait and body weight in the long term in patients with Prader-Willi Syndrome (PWS). Eight adults with PWS were evaluated at baseline and after 7 years. During this period patient participated an in- and out-patient rehabilitation programs including nutritional and adapted physical activity interventions. Two different control groups were included: the first group included 14 non-genetically obese patients (OCG: obese control group) and the second group included 10 age-matched healthy individuals (HCG: healthy control group). All groups were quantitatively assessed during walking with 3D-GA. The results at the 7-year follow-up revealed significant weight loss in the PWS group and spatial-temporal changes in gait parameters (velocity, step length and cadence). With regard to the hip joint, there were significant changes in terms of hip position, which is less flexed. Knee flexion-extension showed a reduction of flexion in swing phase and of its excursion. No changes of the ankle position were evident. As for ankle kinetics, we observed in the second session higher values for the peak of ankle power in terminal stance in comparison to the first session. No changes were found in terms of ankle kinetics. The findings demonstrated improvements associated to long-term weight loss, especially in terms of spatial-temporal parameters and at hip level. Our results back the call for early weight loss interventions during childhood, which would allow the development of motor patterns under normal body weight conditions. PMID:24763375

Cimolin, V; Vismara, L; Galli, M; Grugni, G; Cau, N; Capodaglio, P

2014-07-01

282

Gait analysis and the cumulative gait index (CGI): Translational tools to assess impairments exhibited by rats with olivocerebellar ataxia.  

PubMed

Deviations from 'normal' locomotion exhibited by humans and laboratory animals may be determined using automated systems that capture both temporal and spatial gait parameters. Although many measures generated by these systems are unrelated and independent, some may be related and dependent, representing redundant assessments of function. To investigate this possibility, a treadmill-based system was used to capture gait parameters from normal and ataxic rats, and a multivariate analysis was conducted to determine deviations from normal. Rats were trained on the treadmill at two speeds, and gait parameters were generated prior to and following lesions of the olivocerebellar pathway. Control (non-lesioned) animals exhibited stable hindlimb gait parameters across assessments at each speed. Lesioned animals exhibited alterations in multiple hindlimb gait parameters, characterized by significant increases in stride frequency, braking duration, stance width, step angle, and paw angle and decreases in stride, stance, swing and propulsion durations, stride length and paw area. A principal component analysis of initial hindlimb measures indicated three uncorrelated factors mediating performance, termed Rhythmicity, Thrust and Contact. Deviation in the performance of each animal from the group mean was determined for each factor and values summed to yield the cumulative gait index (CGI), a single value reflecting variation within the group. The CGI for lesioned animals increased 2.3-fold relative to unlesioned animals. This study characterizes gait alterations in laboratory rats rendered ataxic by destruction of the climbing fiber pathway innervating Purkinje cells and demonstrates that a single index can be used to describe overall gait impairments. PMID:25116252

Lambert, C S; Philpot, R M; Engberg, M E; Johns, B E; Kim, S H; Wecker, L

2014-11-01

283

Novel characterization of gait impairments in people with multiple sclerosis by means of the gait profile score.  

PubMed

The assessment of gait abnormalities in individuals with multiple sclerosis (MS) represents a key factor in evaluating the effectiveness of rehabilitation treatments. Despite the availability of sophisticated equipment to objectively evaluate the kinematic aspects of gait, there are still some difficulties in processing the large and complex amount of data they produce in the daily clinical routine. On the basis of the above-mentioned considerations we propose a novel characterization of gait kinematics in individuals with MS, based on a single measure (gait profile score, GPS) obtained from a quantitative three-dimensional analysis of gait performed using an opto-electronic system. We also investigated the correlation between GPS and the Expanded Disability Status Scale (EDSS) values. Thirty-four patients suffering from relapsing-remitting MS (13 female, 21 male, mean age 46.7years) with an EDSS score of ?6 underwent a gait analysis from which the GPS index was calculated. Their results were compared with those of a control group of healthy age- and gender-matched subjects. The GPS of individuals with MS was found significantly higher with respect to controls (9.12° vs. 5.67°, p<0.001) as the result of kinematic differences in gait patterns referring to pelvic tilt and rotation, hip flexion-extension and rotation, knee flexion-extension and ankle dorsi- and plantar-flexion. A moderate correlation was also found between the EDSS score of the participants and their GPS values (r=0.63, p<0.001). The GPS index thus appears suitable to represent gait deviations from physiological patterns in individuals affected by MS and potentially useful in assessing the outcomes related both to rehabilitation programs and pharmacologic/physical therapies. PMID:25073571

Pau, Massimiliano; Coghe, Giancarlo; Atzeni, Claudia; Corona, Federica; Pilloni, Giuseppina; Marrosu, Maria Giovanna; Cocco, Eleonora; Galli, Manuela

2014-10-15

284

The effect of the 'Gait keeper' mutation in the DMRT3 gene on gaiting ability in Icelandic horses.  

PubMed

A nonsense mutation in DMRT3 ('Gait keeper' mutation) has a predominant effect on gaiting ability in horses, being permissive for the ability to perform lateral gaits and having a favourable effect on speed capacity in trot. The DMRT3 mutant allele (A) has been found in high frequency in gaited breeds and breeds bred for harness racing, while other horse breeds were homozygous for the wild-type allele (C). The aim of this study was to evaluate further the effect of the DMRT3 nonsense mutation on the gait quality and speed capacity in the multigaited Icelandic horse and demonstrate how the frequencies of the A- and C- alleles have changed in the Icelandic horse population in recent decades. It was confirmed that homozygosity for the DMRT3 nonsense mutation relates to the ability to pace. It further had a favourable effect on scores in breeding field tests for the lateral gait tölt, demonstrated by better beat quality, speed capacity and suppleness. Horses with the CA genotype had on the other hand significantly higher scores for walk, trot, canter and gallop, and they performed better beat and suspension in trot and gallop. These results indicate that the AA genotype reinforces the coordination of ipsilateral legs, with the subsequent negative effect on the synchronized movement of diagonal legs compared with the CA genotype. The frequency of the A-allele has increased in recent decades with a corresponding decrease in the frequency of the C-allele. The estimated frequency of the A-allele in the Icelandic horse population in 2012 was 0.94. Selective breeding for lateral gaits in the Icelandic horse population has apparently altered the frequency of DMRT3 genotypes with a predicted loss of the C-allele in relatively few years. The results have practical implications for breeding and training of Icelandic horses and other gaited horse breeds. PMID:25073639

Kristjansson, T; Bjornsdottir, S; Sigurdsson, A; Andersson, L S; Lindgren, G; Helyar, S J; Klonowski, A M; Arnason, T

2014-12-01

285

A Novel HMM Distributed Classifier for the Detection of Gait Phases by Means of a Wearable Inertial Sensor Network  

PubMed Central

In this work, we decided to apply a hierarchical weighted decision, proposed and used in other research fields, for the recognition of gait phases. The developed and validated novel distributed classifier is based on hierarchical weighted decision from outputs of scalar Hidden Markov Models (HMM) applied to angular velocities of foot, shank, and thigh. The angular velocities of ten healthy subjects were acquired via three uni-axial gyroscopes embedded in inertial measurement units (IMUs) during one walking task, repeated three times, on a treadmill. After validating the novel distributed classifier and scalar and vectorial classifiers-already proposed in the literature, with a cross-validation, classifiers were compared for sensitivity, specificity, and computational load for all combinations of the three targeted anatomical segments. Moreover, the performance of the novel distributed classifier in the estimation of gait variability in terms of mean time and coefficient of variation was evaluated. The highest values of specificity and sensitivity (>0.98) for the three classifiers examined here were obtained when the angular velocity of the foot was processed. Distributed and vectorial classifiers reached acceptable values (>0.95) when the angular velocity of shank and thigh were analyzed. Distributed and scalar classifiers showed values of computational load about 100 times lower than the one obtained with the vectorial classifier. In addition, distributed classifiers showed an excellent reliability for the evaluation of mean time and a good/excellent reliability for the coefficient of variation. In conclusion, due to the better performance and the small value of computational load, the here proposed novel distributed classifier can be implemented in the real-time application of gait phases recognition, such as to evaluate gait variability in patients or to control active orthoses for the recovery of mobility of lower limb joints. PMID:25184488

Taborri, Juri; Rossi, Stefano; Palermo, Eduardo; Patane, Fabrizio; Cappa, Paolo

2014-01-01

286

Losses of Superconductor Journal Bearing  

NASA Astrophysics Data System (ADS)

A high-temperature superconductor (HTS) journal bearing was studied for rotational loss. Two HTS bearings support the rotor at top and bottom. The rotor weight is 4 kg and the length is about 300 mm. Both the top and bottom bearings have two permanent magnet (PM) rings with an iron pole piece separating them. Each HTS journal bearing is composed of six pieces of superconductor blocks of size 35×25×10 mm. The HTS blocks are encased in a cryochamber through which liquid nitrogen flows. The inner spool of the cryochamber is made from G-10 to reduce eddy current loss, and the rest of the cryochamber is stainless steel. The magnetic field from the PM rings is < 10 mT on the stainless part. The rotational drag was measured over the same speed range at several chamber pressures. Results indicate that a chamber pressure of 0.4 mtorr is sufficiently low to minimize windage loss, and the 10 mT design criterion for the magnetic field on the stainless part of the cryochamber is too high.

Han, Y. H.; Hull, J. R.; Han, S. C.; Jeong, N. H.; Oh, J. M.; Sung, T. H.

2004-06-01

287

Experiments with needle bearings  

NASA Technical Reports Server (NTRS)

Experiments and results are presented in testing needle bearings, especially in comparison with roller bearings. Reduction in coefficient of friction is discussed as well as experimental methods and recording devices.

Ferretti, Pericle

1933-01-01

288

Quantitative Gait Analysis Detects Significant Differences in Movement between Osteoarthritic and Nonosteoarthritic Guinea Pig Strains before and after Treatment with Flunixin Meglumine  

PubMed Central

A computer-aided gait analysis system was used to contrast two guinea pig strains with differing propensity for osteoarthritis (OA), with/without administration of a nonsteroidal anti-inflammatory drug. Walking speed and static/dynamic gait parameters were determined at baseline. Flunixin meglumine was given and animals were evaluated 4, 24, and 72 hours after treatment. Body weight was compared using unpaired t-tests. Knee joints were histologically evaluated using species-specific criteria; indices were analyzed using one-way ANOVA, Kruskal-Wallis test, followed by Dunn's multiple comparisons. A generalized linear model followed by Tukey's posttests juxtaposed gait parameters; walking speed was a covariate for other outcome measures. Body weight was not different between strains; OA-prone animals demonstrated more progressive chondropathy. At baseline, OA-prone animals had slower walking speeds, narrower hind limb bases of support, shorter stride lengths, and slower limb swing speeds relative to OA-resistant animals. These differences were not detected 4 or 24 hours after treatment. By 72 hours, OA-prone animals had returned to baseline values. These findings indicate a distinct voluntary gait pattern in a rodent model of bilateral primary OA, modification of which may allow rapid screening of novel therapies. Flunixin meglumine temporarily permitted OA-prone animals to move in a manner that was analogous to OA-resistant animals. PMID:24963402

Santangelo, K. S.; Kaeding, A. C.; Baker, S. A.; Bertone, A. L.

2014-01-01

289

Axial Halbach Magnetic Bearings  

NASA Technical Reports Server (NTRS)

Axial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control.

Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

2008-01-01

290

Polar Bears Change Diet  

NSDL National Science Digital Library

This radio broadcast from 2001 explains how polar bears have adjusted their diet due to the climate warming around Hudson Bay, Canada. The ringed seals that polar bears normally eat have been harder for polar bears to get to, due to disappearing ice. This has forced polar bears to begin eating harbor seals and bearded seals. The clip is 4 minutes and 15 seconds in length.

Schneider, Doug

2007-12-12

291

Gait control and executive dysfunction in early schizophrenia.  

PubMed

Dysexecutive functioning, which is described as an enduring core feature of schizophrenia, has been associated with gait disorders. However, few studies have reported gait disorders in schizophrenia patients. The objective of this study was to examine the association between executive dysfunction and gait performance in recent-onset schizophrenia patients using the dual task paradigm. Thirty-two subjects participated to the study: 17 with recent-onset schizophrenia and 15 healthy age-matched controls. Executive functions were evaluated using the Frontal Assessment Battery, Stroop and Trail-Making tests. Mean values and coefficients of variation (CV) of the temporal gait parameters while single tasking (just walking) and while dual tasking (walking and forward counting, walking and backward counting, walking and verbal fluency) were measured using the SMTEC(®)-footswitch system. We focused on the CV of stride time as this measure has been shown to be the most representative parameter of higher gait control. A strong effect of the stride time was found in the group factor for the verbal fluency dual-task when compared to controls (Cohen's d mean = 1.28 and CV = 1.05). The effect was lower in the other dual tasks, and insignificant in the single task of walking. This study shows that patients exhibit higher stride-to-stride variability while dual tasking than controls. It also shows a stronger impact of verbal fluency on gait regularity compared to the other dual tasks revealing a relationship between the executive dysfunction and gait modification. Those results are in line with the idea that schizophrenia implies not only cognitive but also motor functioning and coordination impairment. PMID:24201834

Lallart, Elise; Jouvent, Roland; Herrmann, François R; Perez-Diaz, Fernando; Lallart, Xavier; Beauchet, Olivier; Allali, Gilles

2014-04-01

292

Improvements in Sleep Quality and Gait Speed After Cataract Surgery  

PubMed Central

Abstract Background Gait speed and sleep quality are health indices related to longevity and mortality. In the present study, we measured sleep quality, quality of life, gait speed, and visual acuity before and after cataract surgery to evaluate the efficacy of the procedure on systemic health. Methods The study was conducted on 155 patients (93 women; average age 74.8 years) undergoing cataract surgery with the implantation of a yellow soft acrylic lens. Patients were evaluated using the Pittsburgh Sleep Quality Index (PSQI) and the National Eye Institute Visual Function Questionnaire 25 (VFQ-25; vision-related quality of life) before and then 2 and 7 months after surgery. Four-meter gait speed was also determined. Results Of the 155 patients, 68 (43.9%) were classified as poor sleepers (PSQI>5.5) prior to surgery. Significant improvements were noted in sleep 2 months after surgery (p<0.05, paired t-test), but thereafter the improvements were not significant. Prior to surgery, 117 patients (77.0%) were classified as slow walkers (speed<1.0 meter/s). Gait speed increased significantly in these patients 2 months after surgery (p<0.001, paired t-test). Multiple regression analysis revealed significant correlations between the preoperative VFQ-25 score and both PSQI (p<0.05) and gait speed (p<0.001). Postoperative increases in the VFQ-25 score were positively correlated with decreases in the PSQI (p<0.05). Improvements in visual acuity were correlated with improvements in the VFQ-25 score, but not with either PSQI or gait speed. Conclusion Cataract surgery effectively improves sleep quality and slow gait speed. PMID:23145881

Muramatsu, Masahiro; Negishi, Kazuno; Tsubota, Kazuo

2013-01-01

293

Does Anxiety Cause Freezing of Gait in Parkinson's Disease?  

PubMed Central

Individuals with Parkinson's disease (PD) commonly experience freezing of gait under time constraints, in narrow spaces, and in the dark. One commonality between these different situations is that they may all provoke anxiety, yet anxiety has never been directly examined as a cause of FOG. In this study, virtual reality was used to induce anxiety and evaluate whether it directly causes FOG. Fourteen patients with PD and freezing of gait (Freezers) and 17 PD without freezing of gait (Non-Freezers) were instructed to walk in two virtual environments: (i) across a plank that was located on the ground (LOW), (ii) across a plank above a deep pit (HIGH). Multiple synchronized motion capture cameras updated participants' movement through the virtual environment in real-time, while their gait was recorded. Anxiety levels were evaluated after each trial using self-assessment manikins. Freezers performed the experiment on two separate occasions (in their ON and OFF state). Freezers reported higher levels of anxiety compared to Non-Freezers (p<0.001) and all patients reported greater levels of anxiety when walking across the HIGH plank compared to the LOW (p<0.001). Freezers experienced significantly more freezing of gait episodes (p?=?0.013) and spent a significantly greater percentage of each trial frozen (p?=?0.005) when crossing the HIGH plank. This finding was even more pronounced when comparing Freezers in their OFF state. Freezers also had greater step length variability in the HIGH compared to the LOW condition, while the step length variability in Non-Freezers did not change. In conclusion, this was the first study to directly compare freezing of gait in anxious and non-anxious situations. These results present strong evidence that anxiety is an important mechanism underlying freezing of gait and supports the notion that the limbic system may have a profound contribution to freezing in PD. PMID:25250691

Ehgoetz Martens, Kaylena A.; Ellard, Colin G.; Almeida, Quincy J.

2014-01-01

294

Grizzly bears and forestry  

Microsoft Academic Search

Today's growing demand for timber is increasing road development in once roadless forest ecosystems. Roads create both local changes in plant communities and landscape-level changes in forest connectivity. Roads also increase human access, which can be detrimental to species such as grizzly bears. Because most grizzly bear mortalities occur near roads, we examined grizzly bear attractants near roads, which could

C. L. Roever; M. S. Boyce; G. B. Stenhouse

2008-01-01

295

Fault tolerant control of homopolar magnetic bearings and circular sensor arrays  

E-print Network

magnetic suspension system. The homopolar magnetic bearings are biased by permanent magnets to reduce the energy consumption. One control scheme is to adjust system parameters by swapping current distribution matrices for magnetic bearings and weighting...

Li, Ming-Hsiu

2006-04-12

296

Positive force feedback in bouncing gaits?  

PubMed Central

During bouncing gaits (running, hopping, trotting), passive compliant structures (e.g. tendons, ligaments) store and release part of the stride energy. Here, active muscles must provide the required force to withstand the developing tendon strain and to compensate for the inevitable energy losses. This requires an appropriate control of muscle activation. In this study, for hopping, the potential involvement of afferent information from muscle receptors (muscle spindles, Golgi tendon organs) is investigated using a two-segment leg model with one extensor muscle. It is found that: (i) positive feedbacks of muscle-fibre length and muscle force can result in periodic bouncing; (ii) positive force feedback (F+) stabilizes bouncing patterns within a large range of stride energies (maximum hopping height of 16.3 cm, almost twofold higher than the length feedback); and (iii) when employing this reflex scheme, for moderate hopping heights (up to 8.8 cm), an overall elastic leg behaviour is predicted (hopping frequency of 1.4-3 Hz, leg stiffness of 9-27 kN m(-1)). Furthermore, F+ could stabilize running. It is suggested that, during the stance phase of bouncing tasks, the reflex-generated motor control based on feedbacks might be an efficient and reliable alternative to central motor commands. PMID:14561282

Geyer, Hartmut; Seyfarth, Andre; Blickhan, Reinhard

2003-01-01

297

In-home measurement of the effect of strategically weighted vests on ambulation.  

PubMed

Strategically weighted vests are currently being used to treat patients with Parkinson's, Multiple Sclerosis, and ataxia. While studies have been conducted to demonstrate the effectiveness of these vests, there has been very little research into the mechanisms that give rise to the vest's results. This study demonstrates the ability to capture gait parameters from depth images[1] in the home with sufficient sensitivity to support future investigation of the weighted vest intervention. The study also explores multiple metrics, using in-home gait sensing, to study a subject's ambulatory ability including gait mechanics, uncertainty in motion, and gait cadence. We then investigate the effects of these vests on a subject's ambulation by examining these metrics both before and after the vest is worn. While only four subjects were used, results are promising, showing a statistically significant and clinically significant change in many of these metrics as a result of the vest. The cases presented here concern two subjects, one with a "tight" gait caused by Progressive Supranuclear Palsy, and the second with an excessively "loose" gait due to Parkinson's disease. We show that in both subjects, using the vest immediately moved the metrics in a direction beneficial to the subject's clinical condition. This result concurs with clinical observations as measured using various clinical fall risk instruments. PMID:24109846

Wallace, Robert; Abbott, Carmen; Gibson-Horn, Cynthia; Skubic, Marjorie

2013-01-01

298

Cryogenic Hybrid Magnetic Bearing  

NASA Technical Reports Server (NTRS)

Cryogenic hybrid magnetic bearing is example of class of magnetic bearings in which permanent magnets and electromagnets used to suspend shafts. Electromagnets provide active control of position of shaft. Bearing operates at temperatures from -320 degrees F (-196 degrees C) to 650 degrees F (343 degrees C); designed for possible use in rocket-engine turbopumps, where effects of cryogenic environment and fluid severely limit lubrication of conventional ball bearings. This and similar bearings also suitable for terrestrial rotating machinery; for example, gas-turbine engines, high-vacuum pumps, canned pumps, precise gimbals that suspend sensors, and pumps that handle corrosive or gritty fluids.

Meeks, Crawford R.; Dirusso, Eliseo; Brown, Gerald V.

1994-01-01

299

Secure and Privacy Enhanced Gait Authentication on Smart Phone  

PubMed Central

Smart environments established by the development of mobile technology have brought vast benefits to human being. However, authentication mechanisms on portable smart devices, particularly conventional biometric based approaches, still remain security and privacy concerns. These traditional systems are mostly based on pattern recognition and machine learning algorithms, wherein original biometric templates or extracted features are stored under unconcealed form for performing matching with a new biometric sample in the authentication phase. In this paper, we propose a novel gait based authentication using biometric cryptosystem to enhance the system security and user privacy on the smart phone. Extracted gait features are merely used to biometrically encrypt a cryptographic key which is acted as the authentication factor. Gait signals are acquired by using an inertial sensor named accelerometer in the mobile device and error correcting codes are adopted to deal with the natural variation of gait measurements. We evaluate our proposed system on a dataset consisting of gait samples of 34 volunteers. We achieved the lowest false acceptance rate (FAR) and false rejection rate (FRR) of 3.92% and 11.76%, respectively, in terms of key length of 50 bits. PMID:24955403

Choi, Deokjai

2014-01-01

300

Analysis of foot load during ballet dancers' gait.  

PubMed

Ballet is an art that puts extreme demands on the dancer's musculoskeletal system and therefore significantly affects motor behavior of the dancers. The aim of our research was to compare plantar pressure distribution during stance phase of gait between a group of professional ballet dancers and non-dancers. Thirteen professional dancers (5 men, 8 women; mean age of 24.1 ± 3.8 years) and 13 nondancers (5 men, 8 women; mean age of 26.1 ± 5.3 years) participated in this study. Foot pressure analysis during gait was collected using a 2 m pressure plate. The participants were instructed to walk across the platform at a self-selected pace barefoot. Three gait cycles were necessary for the data analysis. The results revealed higher (p < 0.05) pressure peaks in medial edge of forefoot during gait for dancers in comparison with nondancers. Furthermore, differences in total foot loading and foot loading duration of rearfoot was higher (p < 0.05) in dancers as well. We can attribute these differences to long-term and intensive dancing exercises that can change the dancer's gait stereotype. PMID:25088458

Prochazkova, Marketa; Tepla, Lucie; Svoboda, Zdenek; Janura, Miroslav; Cieslarová, Miloslava

2014-01-01

301

Dynamic markers of altered gait rhythm in amyotrophic lateral sclerosis  

NASA Technical Reports Server (NTRS)

Amyotrophic lateral sclerosis (ALS) is a disorder marked by loss of motoneurons. We hypothesized that subjects with ALS would have an altered gait rhythm, with an increase in both the magnitude of the stride-to-stride fluctuations and perturbations in the fluctuation dynamics. To test for this locomotor instability, we quantitatively compared the gait rhythm of subjects with ALS with that of normal controls and with that of subjects with Parkinson's disease (PD) and Huntington's disease (HD), pathologies of the basal ganglia. Subjects walked for 5 min at their usual pace wearing an ankle-worn recorder that enabled determination of the duration of each stride and of stride-to-stride fluctuations. We found that the gait of patients with ALS is less steady and more temporally disorganized compared with that of healthy controls. In addition, advanced ALS, HD, and PD were associated with certain common, as well as apparently distinct, features of altered stride dynamics. Thus stride-to-stride control of gait rhythm is apparently compromised with ALS. Moreover, a matrix of markers based on gait dynamics may be useful in characterizing certain pathologies of motor control and, possibly, in quantitatively monitoring disease progression and evaluating therapeutic interventions.

Hausdorff, J. M.; Lertratanakul, A.; Cudkowicz, M. E.; Peterson, A. L.; Kaliton, D.; Goldberger, A. L.

2000-01-01

302

Weight set  

NSDL National Science Digital Library

Your skin covers and protects your body. Your skin can also detect pressure and weight. You can tell that a one gram weight feels lighter than a one kilogram weight because the receptors on your skin detect more pressure from a one kilogram weight compared to a one gram weight.

N/A N/A (None;)

2005-12-11

303

Temporal and Spatial Characteristics of Gait During Performance of the Dynamic Gait Index in People With and People Without Balance or Vestibular Disorders  

PubMed Central

Background and Purpose: Understanding underlying gait characteristics during performance of the Dynamic Gait Index (DGI) could potentially guide interventions. The purpose of this study was to describe the characteristics and reliability of gait performance during the level walking items of the DGI in people with balance or vestibular dysfunction. The study was a cross-sectional investigation with 2-group comparisons. Subjects and Methods: Forty-seven subjects (mean age=59.2 years, SD=8.5, range=24–90) participated in the study; 26 were control subjects, and 21 were subjects with balance or vestibular dysfunction. Three trials of each level gait item were administered to subjects as they ambulated on an instrumented walkway. Test-retest reliability was determined by use of an intraclass correlation coefficient (3,1) 2-way random-effects model for gait parameters associated with continuous walking and the item requiring turning and stopping quickly. Mean gait parameter differences between control subjects and subjects with balance or vestibular disorders were compared by use of a multivariate analysis of variance for each gait task. Results: The reliability of most gait parameters during DGI performance were fair to excellent between trials. Subjects with balance or vestibular disorders demonstrated differences in gait characteristics compared with control subjects. The heterogeneity of the group of subjects with balance or vestibular disorders does not permit inferences to be drawn regarding the relationship between gait and any specific balance or vestibular diagnosis. The results are most pertinent to people with chronic balance or vestibular disorders. Discussion and Conclusion: Gait parameters underlying dynamic walking appeared to be relatively reliable across multiple trials and distinguished subjects with balance or vestibular disorders. Evaluating a person's performance on items of the DGI may be useful in identifying gait deviations and in evaluating gait improvements as a result of interventions. PMID:18292216

Marchetti, Gregory F; Whitney, Susan L; Blatt, Philip J; Morris, Laura O; Vance, Joan M

2008-01-01

304

A Preliminary Study of Modification of Gait in Real-Time Using Surface Electromyography  

Microsoft Academic Search

Modification of abnormal gait was attempted in real-time using a surface electromyography-based protocol to teach recruitment of the anterior tibialis at the correct time in the gait cycle. Two children diagnosed with cerebral palsy were able to learn volitional control of the anterior tibialis as demonstrated by improved clearance of the toe on the swing phase of the gait and

Jeffrey E. Bolek

2003-01-01

305

Nonlinear dynamical model of human gait Bruce J. West1,2,3  

E-print Network

dynamical model of the human gait control system in a variety of gait regimes. The stride-interval time that the central nervous system is coupled to the motocontrol system, and together they control the locomo- tionNonlinear dynamical model of human gait Bruce J. West1,2,3 and Nicola Scafetta1,2 1 Pratt School

Scafetta, Nicola

306

Phone-based Gait Analysis to Detect Alcohol Usage Hsin-Liu (Cindy) Kao1  

E-print Network

proposes and analyzes a phone-based gait anom- aly detection system targeting the after-effects of alcohol a mobile phone in their trouser pocket and walked 40 meters to record regular gait data. ParticipantsPhone-based Gait Analysis to Detect Alcohol Usage Hsin-Liu (Cindy) Kao1 , Bo-Jhang Ho2 , Allan C

Ouhyoung, Ming

307

Quadrupedal Gait Generation Based on Human Feeling for Robot Assisted Therapy  

Microsoft Academic Search

In the field of pet robots and robot assisted therapy (RAT), animal motion is important for robots resembling various animals. This paper presents a method for the generation of animal gait in quadrupedal robots. In this study, we employ AIBO as an experimental quadrupedal robot and generate the AIBO's gait on the basis of an animal's gait. First, we optimize

Hidekazu Suzuki; Hitoshi Nishi

2008-01-01

308

Two distinct gait types in swimming frogs Sandra Nauwelaerts* and Peter Aerts  

E-print Network

Two distinct gait types in swimming frogs Sandra Nauwelaerts* and Peter Aerts Department of Biology 2001) Abstract During terrestrial locomotion, frogs use two distinct gaits: out-of-phase leg movements velocity- dependent gait shift appears in swimming R. esculenta. Typically, swimming frogs propel

Nauwelaerts, Sandra

309

Learning Gaits for the Stiquito Gary B. Parker, David W. Braun, and Ingo Cyliax  

E-print Network

Genetic Algorithms can be an effective means of gait generation for hexapod robot simulations. They can by human engineers were produced. KEYWORDS: genetic, cyclic, robot, hexapod, gait, control 1. INTRODUCTION The development of learning algorithms for generating hexapod gaits is an important step in the realization

Parker, Gary B.

310

The Incremental Evolution of Gaits for Hexapod Robots Gary B. Parker  

E-print Network

The Incremental Evolution of Gaits for Hexapod Robots Gary B. Parker Computer Science Connecticut College New London, CT 06320 parker@conncoll.edu Abstract Gait control programs for hexapod robots. In this paper, we describe an application of this method to learn gaits for an actual hexapod robot. A cyclic

Parker, Gary B.

311

Determination of the step duration of gait initiation using a mechanical energy analysis  

Microsoft Academic Search

The analysis of gait initiation (the transient state between standing and walking) is an important diagnostic tool in the study of pathologic gait and the evaluation of prosthetic devices. Therefore it is important to know the step duration of gait initiation. However, there is little agreement in the literature regarding this step duration, since each author has based their conclusion

Christopher A. Miller; Mary C. Verstraete

1996-01-01

312

Gait Pattern Differences between Children with Mild Scoliosis and Children with Unilateral Cerebral Palsy  

PubMed Central

This study was conducted to investigate the effects of asymmetrical body posture alone, i.e., the effects seen in children with mild scoliosis, vs. the effects of body posture control impairment, i.e., those seen in children with unilateral cerebral palsy on gait patterns. Three-dimensional instrumented gait analysis (3DGA) was conducted in 45 children with hemiplegia and 51 children with mild scoliosis. All the children were able to walk without assistance devices. A set of 35 selected spatiotemporal gait and kinematics parameters were evaluated when subjects walked on a treadmill. A cluster analysis revealed 3 different gait patterns: a scoliotic gait pattern and 2 different hemiplegic gait patterns. The results showed that the discrepancy in gait patterns was not simply a lower limb kinematic deviation in the sagittal plane, as expected. Additional altered kinematics, such as pelvic misorientation in the coronal plane in both the stance and swing phases and inadequate stance phase hip ad/abduction, which resulted from postural pattern features, were distinguished between the 3 gait patterns. Our study provides evidence for a strong correlation between postural and gait patterns in children with unilateral cerebral palsy. Information on differences in gait patterns may be used to improve the guidelines for early therapy for children with hemiplegia before abnormal gait patterns are fully established. The gait pathology characteristic of scoliotic children is a potential new direction for treating scoliosis that complements the standard posture and walking control therapy exercises with the use of biofeedback. PMID:25089908

Domagalska-Szopa, Malgorzata; Szopa, Andrzej

2014-01-01

313

Gait Rehabilitation Therapy Using Robot Generated Force Fields Applied at the Pelvis  

E-print Network

Gait Rehabilitation Therapy Using Robot Generated Force Fields Applied at the Pelvis ABSTRACT The Robotic Gait Rehabilitation (RGR) Trainer was designed and built to target secondary gait deviations, which generate corrective forces as a response to deviations from normal pelvic motion. The device

Mavroidis, Constantinos

314

Tracking of Thigh Flexion Angle during Gait Cycles in an Ambulatory Activity Monitoring Sensor Network1)  

Microsoft Academic Search

An accelerometry-based gait analysis approach via the platform of sensor network is reported in this paper. The hardware units of the sensor network are wearable accelerometers that are attached at the limbs of human body. For the specific task of gait analysis, flexion angles of the thighs during gait cycles are computed. A Kalman filter is designed to estimate the

DONG Liang; WU Jian-Kang; BAO Xiao-Ming; XIAO Wen-Dong

315

Development of an affordable system for 2D kinematics and dynamics analysis of human gait  

NASA Astrophysics Data System (ADS)

Development of a low-cost, yet reliable, system for 2D gait analysis is presented in this paper. The system consists of a home video camera with speed of 25 fps, LED markers, PC and a technical computing software, which are used for capturing and processing the digital image of markers attached to human body during motion. In the experiments, a person is instructed to walk in a specially arranged measurement area. The recorded images are then digitally processed to detect and track the 2D coordinate of the markers over time. To conduct a dynamics analysis, a mathematical formulation for human motion is constructed where the body is modeled by a system of five rigid bars connected by joints. Finally, a program is developed to plot and calculate the kinematics and dynamics data of human gait, where the markers position data over time, and other variables such as dimensions and weight of the body are used as the input in the program.

Mahyuddin, A. I.; Mihradi, S.; Dirgantara, T.; Sukmajaya, A.; Juliyad, N.; Purba, U.

2010-03-01

316

Development of an affordable system for 2D kinematics and dynamics analysis of human gait  

NASA Astrophysics Data System (ADS)

Development of a low-cost, yet reliable, system for 2D gait analysis is presented in this paper. The system consists of a home video camera with speed of 25 fps, LED markers, PC and a technical computing software, which are used for capturing and processing the digital image of markers attached to human body during motion. In the experiments, a person is instructed to walk in a specially arranged measurement area. The recorded images are then digitally processed to detect and track the 2D coordinate of the markers over time. To conduct a dynamics analysis, a mathematical formulation for human motion is constructed where the body is modeled by a system of five rigid bars connected by joints. Finally, a program is developed to plot and calculate the kinematics and dynamics data of human gait, where the markers position data over time, and other variables such as dimensions and weight of the body are used as the input in the program.

Mahyuddin, A. I.; Mihradi, S.; Dirgantara, T.; Sukmajaya, A.; Juliyad, N.; Purba, U.

2009-12-01

317

Estimate of lower trunk angles in pathological gaits using gyroscope data.  

PubMed

Trunk mobility impairment can cause balance, postural and gait challenges during overground level walking in patients with different pathologies. Assessment of the rotations of the trunk during walking with an abnormal gait can provide knowledge required for a better understanding of the nature of the motor control deficit and support decision-making in patient rehabilitation. A method based on the use of a weighted Fourier linear combiner (WFLC) adaptive filter is proposed in this paper for the estimation of lower trunk angles during pathological overground level walking, using angular velocities measured at the lower trunk level with a wearable inertial sensor. This method was validated for a group of 24 patients, 13 with hemiplegia and 11 with Parkinson's disease, by comparing the estimated angles to those simultaneously obtained from a stereophotogrammetric system. Analysis of the root mean square error, correlation coefficient and offset results revealed that the WFLC approach is highly accurate in estimating lateral and frontal bending and axial rotations of the lower trunk in pathological level walking. PMID:23497803

Grimpampi, Eleni; Bonnet, Vincent; Taviani, Antonio; Mazzà, Claudia

2013-07-01

318

SIZE AND GROWTH PATTERNS OF THE YELLOWSTONE GRIZZLY BEAR  

Microsoft Academic Search

Weights and\\/or measurements of 151 grizzly bears (Ursus arctos) captured 261 times were recorded from 1975 to 1985. Males were consistently heavier than females within all age classes beginning at age 2. Mean weight for 65 adult males (5+ years old) was 192 kg and 135 kg for 63 adult females (5 + years old). Mean monthly weights by sex

BONNIE M. BLANCHARD

319

Gait apraxia after bilateral supplementary motor area lesion  

PubMed Central

Objectives: The study aimed at addressing the issue of the precise nature of gait apraxia and the cerebral dysfunction responsible for it. Methods: The case of a patient, affected by a bilateral infarction limited to a portion of the anterior cerebral artery territory is reported. The patient's ability to walk was formally assessed by means of a new standardised test. Results: Due to an anomaly within the anterior cerebral artery system, the patient's lesion was centred on the supplementary motor regions of both hemispheres. He presented with clear signs of gait apraxia that could not be accounted for by paresis or other neurological deficits. No signs of any other form of apraxia were detected. Conclusions: The clinical profile of the patient and the analysis of 49 cases from previous literature suggest that gait apraxia should be considered a clinical entity in its own right and lesions to the supplementary motor areas are responsible for it. PMID:11784830

Della, S; Francescani, A; Spinnler, H

2002-01-01

320

Inhibition, Executive Function, and Freezing of Gait  

PubMed Central

Background Studies suggest that freezing of gait (FoG) in people with Parkinson’s disease (PD) is associated with declines in executive function (EF). However, EF is multi-faceted, including three dissociable components: inhibiting prepotent responses, switching between task sets, and updating working memory. Objective This study investigated which aspect of EF is most strongly associated with FoG in PD. Method Three groups were studied: adults with PD (with and without FoG) and age-matched, healthy adults. All participants completed a battery of cognitive tasks previously shown to discriminate among the three EF components. Participants also completed a turning-in-place task that was scored for FoG by neurologists blind to subjects’ self-reported FoG. Results Compared to both other groups, participants with FoG showed significant performance deficits in tasks associated with inhibitory control, even after accounting for differences in disease severity, but no significant deficits in task-switching or updating working memory. Surprisingly, the strongest effect was an intermittent tendency of participants with FoG to hesitate, and thus miss the response window, on go trials in the Go-Nogo task. The FoG group also made slower responses in the conflict condition of the Stroop task. Physician-rated FoG scores were correlated both with failures to respond on go trials and with failures to inhibit responses on nogo trials in the Go-Nogo task. Conclusion These results suggest that FoG is associated with a specific inability to appropriately engage and release inhibition, rather than with a general executive deficit. PMID:24496099

Cohen, Rajal G.; Klein, Krystal A.; Nomura, Mariko; Fleming, Michael; Mancini, Martina; Giladi, Nir; Nutt, John G.; Horak, Fay B.

2014-01-01

321

Subtle gait changes in patients with REM sleep behavior disorder.  

PubMed

Many people with rapid eye movement (REM) sleep behavior disorder (RBD) have an underlying synucleinopathy, the most common of which is Lewy body disease. Identifying additional abnormal clinical features may help in identifying those at greater risk of evolving to a more severe syndrome. Because gait disorders are common in the synucleinopathies, early abnormalities in gait in those with RBD could help in identifying those at increased risk of developing overt parkinsonism and/or cognitive impairment. We identified 42 probable RBD subjects and 492 controls using the Mayo Sleep Questionnaire and assessed gait velocity, cadence, and stride dynamics with an automated gait analysis system. Cases and controls were similar in age (79.9?±?4.7 and 80.1?±?4.7, P?=?0.74), Unified Parkinson's Disease Rating Scale Part III (UPDRS) score (3.3?±?5.5 and 1.9?±?4.1, P?=?0.21) and Mini-Mental State Examination scores (27.2?±?1.9 and 27.7?±?1.6, P?=?0.10). A diagnosis of probable RBD was associated with decreased velocity (-7.9 cm/s; 95% confidence interval [CI], -13.8 to -2.0; P?gait changes prior to overt clinical parkinsonism. Diagnosis of probable RBD supplemented by gait analysis may help as a screening tool for disorders of ?-synuclein. PMID:24130124

McDade, Eric M; Boot, Brendon P; Christianson, Teresa J H; Pankratz, V Shane; Boeve, Bradley F; Ferman, Tanis J; Bieniek, Kevin; Hollman, John H; Roberts, Rosebud O; Mielke, Michelle M; Knopman, David S; Petersen, Ronald C

2013-11-01

322

Classification of gait disturbances: distinguishing between continuous and episodic changes  

PubMed Central

The increased awareness of the importance of gait and postural control to quality of life and functional independence has led many research groups to study the patho-physiology, epidemiology, clinical, and therapeutic aspects of these motor functions. In recognition of the increased awareness of the significance of this topic, the Movement Disorders Journal is devoting this entire issue to gait and postural control. Leading research groups provide critical reviews of the current knowledge and propose future directions for this evolving field. The results of a large randomized controlled trial designed to reduce falls and improve mobility in people with Parkinson’s disease is also included in this issue. The intensive work in this area throughout the world has created an urgent need for a unified language. Because gait and postural disturbances are so common, the clinical classification should be clear, straightforward and simple to use. As an introduction to this special issue, we propose a new clinically based classification scheme that is organized according to the dominant observed disturbance, while taking into an account the results of a basic neurological exam. The proposed classification differentiates between continuous and episodic gait disturbances since this subdivision has important ramifications from the functional, prognostic and mechanistic perspectives. We anticipate that research into gait and postural control will continue to flourish over the next decade as the search for new ways of promoting mobility and independence aims to keep up with the exponentially growing population of aging older adults. Hopefully, this new classification scheme and the papers focusing on gait and postural control in this special issue of the Movement Disorders Journal will help to facilitate future investigations in this exciting and rapidly growing area. PMID:24132835

Giladi, Nir; Horak, Fay B; Hausdorff, Jeffrey M.

2013-01-01

323

Subtle gait changes in patients with REM Behavior Disorder  

PubMed Central

Background Many people with REM sleep behavior disorder have an underlying synucleinopathy, the most common of which is Lewy body disease. Identifying additional abnormal clinical features may help in identifying those at greater risk of evolving to a more severe syndrome. As gait disorders are common in the synucleinopathies, early abnormalities in gait in those with REM sleep behavior disorder could help in identifying those at increased risk of developing overt parkinsonism and/or cognitive impairment. Methods We identified 42 probable REM sleep behavior disorder subjects and 492 controls using the Mayo Sleep Questionnaire and assessed gait velocity, cadence and stride dynamics with an automated gait analysis system. Results Cases and controls were similar in age (79.9 ± 4.7 & 80.1 ± 4.7, p= 0.74), UPDRS score (3.3 ± 5.5 & 1.9 ± 4.1, p=0.21) and Mini-Mental State Examination scores (27.2 ± 1.9 & 27.7 ± 1.6, p=0.10). A diagnosis of probable REM sleep behavior disorder was associated with decreased velocity (?7.9 cm/sec, 95%CI ?13.8 to ?2.0, p<0.01), cadence (?4.4 steps/min, 95%CI ?7.6 to ?1.3, p<0.01), and significantly increased double limb support variability (30%, 95%CI 6 – 60, p=0.01), greater stride time variability (29%, 95%CI 2 – 63, p=0.03) and swing time variability (46%, 95%CI 15 – 84, p<0.01). Conclusions Probable REM sleep behavior disorder is associated with subtle gait changes prior to overt clinical parkinsonism. Diagnosis of probable REM sleep behavior disorder supplemented by gait analysis may help as a screening tool for disorders of ?-synuclein. PMID:24130124

McDade, Eric M; Boot, Brendon P.; Christianson, Teresa JH; Pankratz, V. Shane; Boeve, Bradley F; Ferman, Tanis J.; Bieniek, Kevin; Hollman, John H; Roberts, Rosebud O; Mielke, Michelle M; Knopman, David S.; Petersen, Ronald C.

2013-01-01

324

Implementing gait pattern control and transition for legged locomotion  

NASA Astrophysics Data System (ADS)

In this work, a generalised central pattern generator (CPG) model is formulated to generate a full range of gait patterns for a hexapod insect. To this end, a recurrent neuronal network module, as the building block for rhythmic patterns, is proposed to extend the concept of oscillatory building blocks (OBB) for constructing a CPG model. The model is able to make transitions between different gait patterns by simply adjusting one model parameter. Simulation results are further presented to show the effectiveness and performance of the CPG network.

Yang, Zhijun; Rocha, Marlon V.; Lima, Priscila M. V.; Karamanoglu, Mehmet; França, Felipe M. G.

2014-07-01

325

Stroke Survivors' Gait Adaptations to a Powered Ankle Foot Orthosis  

PubMed Central

Background and Purpose Stroke is the leading cause of long term disability in the United States, and for many it causes loss of gait function. The purpose of this research is to examine stroke survivors’ gait adaptations to training on the Powered Ankle Foot Orthosis (PAFO). Of particular interest is the stroke survivors’ ability to learn how to store and release energy properly while using the device. The PAFO utilizes robotic tendon technology and supports motion with a single degree of freedom, ankle rotation in the sagittal plane. This actuator comprises a motor and series spring. The user interacts with the output side of the spring while the robot controls the input side of the spring such that typical able body ankle moments would be generated, assuming able body ankle kinematics are seen at the output side of the spring. Methods Three individuals post-stroke participated in a three week training protocol. Outcome measures (temporal, kinematic, and kinetic) were derived from robot sensors and recorded for every step. These data are used to evaluate each stroke survivor’s adaptations to robotic gait assistance. The robot was worn only on the paretic ankle. For validation of the kinematic results, motion capture data were collected on the third subject. Results All subjects showed increased cadence, ankle range of motion, and power generation capabilities. Additionally, all subjects were able to achieve a larger power output than power input from the robot. Motion capture data collected from subject three validated the robot sensor kinematic data on the affected side, but also demonstrated an unexpected gait adaptation on the unaffected ankle. Conclusions Sensors on the gait assisting robot provide large volumes of valuable information on how gait parameters change over time. We have developed key gait evaluation metrics based on the available robot sensor information that may be useful to future researchers. All subjects adapted their gait to the robotic assistance, and many of their key metrics moved closer to typical able body values. This suggests that each subject learned to utilize the assistive moments generated by the robot, despite having no predefined ankle trajectory input from the robot. The security of being harnessed on the treadmill led to more dramatic and favorable results. PMID:25339789

Ward, Jeffrey; Sugar, Thomas; Boehler, Alexander; Standeven, John; Engsberg, Jack R.

2014-01-01

326

Clumping Properties of Content-Bearing Words.  

ERIC Educational Resources Information Center

Defines the notion of serial clustering of words in text, and explores the value of such clustering as an indicator of a word's bearing content. This approach is flexible in the sense that it is context-sensitive; a numerical approach may also be of value in assigning weights to terms in requests. Experimental support is obtained from natural text…

Bookstein, A.; Klein, S. T.; Raita, T.

1998-01-01

327

Verification of predicted knee replacement kinematics during simulated gait in the Kansas knee simulator.  

PubMed

Evaluating total knee replacement kinematics and contact pressure distributions is an important element of preclinical assessment of implant designs. Although physical testing is essential in the evaluation process, validated computational models can augment these experiments and efficiently evaluate perturbations of the design or surgical variables. The objective of the present study was to perform an initial kinematic verification of a dynamic finite element model of the Kansas knee simulator by comparing predicted tibio- and patellofemoral kinematics with experimental measurements during force-controlled gait simulation. A current semiconstrained, cruciate-retaining, fixed-bearing implant mounted in aluminum fixtures was utilized. An explicit finite element model of the simulator was developed from measured physical properties of the machine, and loading conditions were created from the measured experimental feedback data. The explicit finite element model allows both rigid body and fully deformable solutions to be chosen based on the application of interest. Six degrees-of-freedom kinematics were compared for both tibio- and patellofemoral joints during gait loading, with an average root mean square (rms) translational error of 1.1 mm and rotational rms error of 1.3 deg. Model sensitivity to interface friction and damping present in the experimental joints was also evaluated and served as a secondary goal of this paper. Modifying the metal-polyethylene coefficient of friction from 0.1 to 0.01 varied the patellar flexion-extension and tibiofemoral anterior-posterior predictions by 7 deg and 2 mm, respectively, while other kinematic outputs were largely insensitive. PMID:20670059

Halloran, Jason P; Clary, Chadd W; Maletsky, Lorin P; Taylor, Mark; Petrella, Anthony J; Rullkoetter, Paul J

2010-08-01

328

Bearings: Technology and needs  

NASA Technical Reports Server (NTRS)

A brief status report on bearing technology and present and near-term future problems that warrant research support is presented. For rolling element bearings a material with improved fracture toughness, life data in the low Lambda region, a comprehensive failure theory verified by life data and incorporated into dynamic analyses, and an improved corrosion resistant alloy are perceived as important needs. For hydrodynamic bearings better definition of cavitation boundaries and pressure distributions for squeeze film dampers, and geometry optimization for minimum power loss in turbulent film bearings are needed. For gas film bearings, foil bearing geometries that form more nearly optimum film shapes for maximum load capacity, and more effective surface protective coatings for high temperature operation are needed.

Anderson, W. J.

1982-01-01

329

The Incredible Water Bear  

NSDL National Science Digital Library

This image-rich Micscape Magazine article explores how water bears can be found almost everywhere yet are still unknown to almost everybody, why there are relatively few light microscope photographs of water bears in the literature and on the Web, and how light microscopy can outperform scanning electron microscopy when viewing these animals. It includes a list of historical references, early sketches, and colorful images of water bears, also known as tardigrades.

Mach, Martin; Magazine, Micscape

330

Bear Spray Safety Program  

USGS Publications Warehouse

A bear spray safety program for the U.S. Geological Survey (USGS) was officially initiated by the Firearms Safety Committee to address accident prevention and to promote personnel training in bear spray and its transportation, storage, and use for defense against wild animals. Used as part of a system including firearms, or used alone for those who choose not to carry a firearm, bear spray is recognized as an effective tool that can prevent injury in a wild animal attack.

Blome, C.D.; Kuzniar, R.L.

2009-01-01

331

Novel bidirectional air bearing  

NASA Astrophysics Data System (ADS)

Fluid lubricated bearings (ball or journal) exhibit problems of life and contamination in high speed polygonal scanners, particularly at speeds above 15,000 rpm. Grooved air bearings are limited to relatively high manufacturing cost, vertical only attitude, unidirectional rotation, and they tend to ingest debris. A plain journal air bearing is described which is bidirectional, any attitude operation, is free of whirl instability and has low manufacturing cost.

Sherman, Randy J.

1993-12-01

332

Abnormal joint torque patterns exhibited by chronic stroke subjects while walking with a prescribed physiological gait pattern  

Microsoft Academic Search

BACKGROUND: It is well documented that individuals with chronic stroke often exhibit considerable gait impairments that significantly impact their quality of life. While stroke subjects often walk asymmetrically, we sought to investigate whether prescribing near normal physiological gait patterns with the use of the Lokomat robotic gait-orthosis could help ameliorate asymmetries in gait, specifically, promote similar ankle, knee, and hip

Nathan D Neckel; Natalie Blonien; Diane Nichols; Joseph Hidler

2008-01-01

333

Gait Strategy in Patients with Ehlers-Danlos Syndrome Hypermobility Type: A Kinematic and Kinetic Evaluation Using 3D Gait Analysis  

ERIC Educational Resources Information Center

The aim of this study was to quantify the gait patterns of adults with joint hypermobility syndrome/Ehlers-Danlos syndrome (JHS/EDS-HT) hypermobility type, using Gait Analysis. We quantified the gait strategy in 12 JHS/EDS-HT adults individuals (age: 43.08 + 6.78 years) compared to 20 healthy controls (age: 37.23 plus or minus 8.91 years), in…

Galli, Manuela; Cimolin, Veronica; Rigoldi, Chiara; Castori, Marco; Celletti, Claudia; Albertini, Giorgio; Camerota, Filippo

2011-01-01

334

Parallel Factor Analysis of gait waveform data: A multimode extension of Principal Component Analysis.  

PubMed

Gait data are typically collected in multivariate form, so some multivariate analysis is often used to understand interrelationships between observed data. Principal Component Analysis (PCA), a data reduction technique for correlated multivariate data, has been widely applied by gait analysts to investigate patterns of association in gait waveform data (e.g., interrelationships between joint angle waveforms from different subjects and/or joints). Despite its widespread use in gait analysis, PCA is for two-mode data, whereas gait data are often collected in higher-mode form. In this paper, we present the benefits of analyzing gait data via Parallel Factor Analysis (Parafac), which is a component analysis model designed for three- or higher-mode data. Using three-mode joint angle waveform data (subjects×time×joints), we demonstrate Parafac's ability to (a) determine interpretable components revealing the primary interrelationships between lower-limb joints in healthy gait and (b) identify interpretable components revealing the fundamental differences between normal and perturbed subjects' gait patterns across multiple joints. Our results offer evidence of the complex interconnections that exist between lower-limb joints and limb segments in both normal and abnormal gaits, confirming the need for the simultaneous analysis of multi-joint gait waveform data (especially when studying perturbed gait patterns). PMID:21925756

Helwig, Nathaniel E; Hong, Sungjin; Polk, John D

2012-06-01

335

The relationship between clinical measurements and gait analysis data in children with cerebral palsy.  

PubMed

Spasticity is a common impairment that interferes with motor function (particularly gait pattern) in children with cerebral palsy (CP). Gait analysis and clinical measurements are equally important in evaluating and treating gait disorders in children with CP. This study aimed to explore the relationship between the spasticity of lower extremity muscles and deviations from the normal gait pattern in children with CP. Thirty-six children with spastic CP (18 with spastic hemiplegia [HS] and 18 with spastic diplegia [DS]), ranging in age from 7 to 12 years, participated in the study. The children were classified as level I (n=24) or level II (n=12) according to the Gross Motor Function Classification System. Spasticity levels were evaluated with the Dynamic Evaluation of Range of Motion (DAROM) using the accelerometer-based system, and gait patterns were evaluated with a three dimensional gait analysis using the Zebris system (Isny, Germany). The Gillette Gait Index (GGI) was calculated from the gait data. The results show that gait pathology in children with CP does not depend on the static and dynamic contractures of hip and knee flexors. Although significant correlations were observed for a few clinical measures with the gait data (GGI), the correlation coefficients were low. Only the spasticity of rectus femoris showed a fair to moderate correlation with GGI. In conclusion, the results indicate the independence of the clinical evaluation and gait pattern and support the view that both factors provide important information about the functional problems of children with CP. PMID:23810569

Domagalska, Ma?gorzata; Szopa, Andrzej; Syczewska, Ma?gorzata; Pietraszek, Stanis?aw; Kido?, Zenon; Onik, Grzegorz

2013-09-01

336

Is human gait initiation program affected by a reduction of the postural basis?  

PubMed

The aim of this study was to access the adaptability of the gait initiation program by imposing before and during gait a posture that partially prevents the backward shift of the center of foot pressure. Six healthy subjects performed normal gait in the control situation (CS) and gait in the absence of heel ground contact in the test situation (TS) on a force platform at three different speed conditions. It is shown that an increase in the duration of the anticipation phase in TS is necessary to create conditions for progression which allow the subjects to reach a gait velocity similar to the one obtained in CS at the end of the anticipatory movements and also at the end of the first step. Modifications of the gait initiation program occur in order to fulfil the performance in terms of gait velocity. PMID:10793249

Couillandre, A; Brenière, Y; Maton, B

2000-05-12

337

Multilinear modeling for robust identity recognition from gait Fabio Cuzzolin  

E-print Network

identification systems for surveillance and security started to enjoy widespread diffusion. Biometrics like face the adoption of gait recognition systems in real-world scenarios is the influence of a large number of so, lightning, camera setup (viewpoint), but also footwear and clothing, carrying conditions, time of execution

Cuzzolin, Fabio

338

Dynamic stability gait planning of kid humanoid robot  

Microsoft Academic Search

We adopt multi-point planning method based on cubic spline function to perform parametric design of dynamic walking. The objective of optimization is to achieve maximum ZMP stability and minimum joint driving torque, together with the combination of multi-objective genetic algorithm to optimize the gait parameters. Simulation verification has also been carried out in ADAMS and Matlab after optimization. In addition,

Jie Zhao; Le Qi; Jihong Yan; Yanhe Zhu

2009-01-01

339

Gait Development during Lifespan in Subjects with Down Syndrome  

ERIC Educational Resources Information Center

In this work we studied and evaluated the effects of aging in a group of individuals with Down syndrome, using gait analysis as tool of investigation. 32 individuals suffering from Down syndrome (DS) were enrolled in this study as group of pathological participants. The control group (CG) was composed by 36 healthy subjects (10 children, 15…

Rigoldi, Chiara; Galli, Manuela; Albertini, Giorgio

2011-01-01

340

Virtual Sensory Feedback for Gait Improvement in Neurological Patients  

PubMed Central

We review a treatment modality for movement disorders by sensory feedback. The natural closed-loop sensory-motor feedback system is imitated by a wearable virtual reality apparatus, employing body-mounted inertial sensors and responding dynamically to the patient’s own motion. Clinical trials have shown a significant gait improvement in patients with Parkinson’s disease using the apparatus. In contrast to open-loop devices, which impose constant-velocity visual cues in a “treadmill” fashion, or rhythmic auditory cues in a “metronome” fashion, requiring constant vigilance and attention strategies, and, in some cases, instigating freezing in Parkinson’s patients, the closed-loop device improved gait parameters and eliminated freezing in most patients, without side effects. Patients with multiple sclerosis, previous stroke, senile gait, and cerebral palsy using the device also improved their balance and gait substantially. Training with the device has produced a residual improvement, suggesting virtual sensory feedback for the treatment of neurological movement disorders. PMID:24133478

Baram, Yoram

2013-01-01

341

White matter microstructural organization and gait stability in older adults  

PubMed Central

Understanding age-related decline in gait stability and the role of alterations in brain structure is crucial. Here, we studied the relationship between white matter microstructural organization using Diffusion Tensor Imaging (DTI) and advanced gait stability measures in 15 healthy young adults (range 18–30 years) and 25 healthy older adults (range 62–82 years). Among the different gait stability measures, only stride time and the maximum Lyapunov exponent (which quantifies how well participants are able to attenuate small perturbations) were found to decline with age. White matter microstructural organization (FA) was lower throughout the brain in older adults. We found a strong correlation between FA in the left anterior thalamic radiation and left corticospinal tract on the one hand, and step width and safety margin (indicative of how close participants are to falling over) on the other. These findings suggest that white matter FA in tracts connecting subcortical and prefrontal areas is associated with the implementation of an effective stabilization strategy during gait. PMID:24959139

Bruijn, Sjoerd M.; Van Impe, Annouchka; Duysens, Jacques; Swinnen, Stephan P.

2014-01-01

342

Most frequent gait patterns in diplegic spastic cerebral palsy  

PubMed Central

OBJECTIVE: To identify gait patterns in a large group of children with diplegic cerebral palsy and to characterize each group according to age, Gross Motor Function Classification System (GMFCS) level, Gait Deviation Index (GDI) and previous surgical procedures. METHODS: One thousand eight hundred and five patients were divided in seven groups regarding observed gait patterns: jump knee, crouch knee, recurvatum knee, stiff knee, asymmetric, mixed and non-classified. RESULTS: The asymmetric group was the most prevalent (48.8%). The jump knee (9.6 years old) and recurvatum (9.4 years old) groups had mean age lower than the other groups. The lowest GDI (43.58) was found in the crouch group. There were more children classified within GMFCS level III in the crouch and mixed groups. Previous surgical procedures on the triceps surae were more frequent in stiff knee and mixed groups. The jump knee group received less and the stiff-knee group more surgical procedures at hamstrings than others. CONCLUSIONS: The asymmetrical cases were the most frequent within a group of diplegic patients. Individuals with crouch gait pattern were characterized by the lowest GDI and the highest prevalence of GMFCS III, while patients with stiff knee exhibited a higher percentage of previous hamstring lengthening in comparison to the other groups. Level of Evidence III, Retrospective Comparative Study. PMID:25246849

de Morais, Mauro Cesar; Kawamura, Catia Miyuki; Lopes, Jose Augusto Fernandes; Neves, Daniella Lins; Cardoso, Michelle de Oliveira; Caiafa, Jordana Brandao

2014-01-01

343

Understanding the complexity of human gait dynamics Nicola Scafetta,1  

E-print Network

-way interaction between the neural networks in the central nervous system plus the intraspinal nervous system the muscles receive commands from the nervous system, they also send back sensory information that modifiesUnderstanding the complexity of human gait dynamics Nicola Scafetta,1 Damiano Marchi,2 and Bruce J

Scafetta, Nicola

344

Gait Cycle Repeatability The Variance Ratio quantifies the  

E-print Network

activity from the muscles dynamic surface pressure. The MKI and EMG records of the leg muscles of a subject-forms for multiple (8) gait cycles: MKI signals are significantly more similar from cycle to cycle than EMG signals are, even after enveloping EMG Muscle Timing The post-heelstrike timing of the onset and offset of EMG

Craelius, William

345

Reflex Control of Robotic Gait Using Human Walking Data  

PubMed Central

Control of human walking is not thoroughly understood, which has implications in developing suitable strategies for the retraining of a functional gait following neurological injuries such as spinal cord injury (SCI). Bipedal robots allow us to investigate simple elements of the complex nervous system to quantify their contribution to motor control. RunBot is a bipedal robot which operates through reflexes without using central pattern generators or trajectory planning algorithms. Ground contact information from the feet is used to activate motors in the legs, generating a gait cycle visually similar to that of humans. Rather than developing a more complicated biologically realistic neural system to control the robot's stepping, we have instead further simplified our model by measuring the correlation between heel contact and leg muscle activity (EMG) in human subjects during walking and from this data created filter functions transferring the sensory data into motor actions. Adaptive filtering was used to identify the unknown transfer functions which translate the contact information into muscle activation signals. Our results show a causal relationship between ground contact information from the heel and EMG, which allows us to create a minimal, linear, analogue control system for controlling walking. The derived transfer functions were applied to RunBot II as a proof of concept. The gait cycle produced was stable and controlled, which is a positive indication that the transfer functions have potential for use in the control of assistive devices for the retraining of an efficient and effective gait with potential applications in SCI rehabilitation. PMID:25347544

Macleod, Catherine A.; Meng, Lin; Conway, Bernard A.; Porr, Bernd

2014-01-01

346

Feasibility study on iPhone accelerometer for gait detection  

Microsoft Academic Search

Falls amongst the elderly is becoming a major problem with over 50% of elderly hospitalizations due to injury from fall related accidents. Healthcare expenses are dramatically rising due to growing elderly population. Many current technologies for gait analysis are laboratory-based and can incur substantial costs for the healthcare sector for treatment of falls. However utilization of alternative commercially available technologies

Herman K. Y. Chan; Huiru Zheng; Haiying Wang; Rachel Gawley; Mingjing Yang; Roy Sterritt

2011-01-01

347

The effect of divided attention on gait stability following concussion  

Microsoft Academic Search

Background. The need to identify functional impairment following a brain injury is critical to prevent re-injury during the period of recovery. While many neuropsychological tests have been developed to assess cognitive performance, relatively little information on gait and dynamic stability is available on motor task performance for young adults following concussion. This study was performed to investigate the effect of

Tonya M. Parker; Louis R. Osternig; Heng-Ju Lee; Paul van Donkelaar; Li-Shan Chou

2005-01-01

348

Normalisation of gait EMGs: a re-examination  

Microsoft Academic Search

The purpose of this study was to compare four different methods of normalising electromyograms (EMGs) recorded during normal gait. Comparisons were made between the amplitude, intra-individual variability and inter-individual variability of EMGs. Surface EMGs were recorded from the biceps femoris, semitendinosus, vastus lateralis and vastus medialis of ten males and two females while they walked on a treadmill at a

A. M. Burden; M. Trew; V. Baltzopoulos

2003-01-01

349

Fitness Biasing to Produce Adaptive Gaits for Hexapod Robots  

E-print Network

Fitness Biasing to Produce Adaptive Gaits for Hexapod Robots Gary B. Parker Computer Science was shown in an earlier work to be an effective tool for learning leg cycles for a hexapod robot for hexapod robots is a difficult problem. It is particularly challenging if one wants these programs

Parker, Gary B.

350

Joint moment control of mechanical energy flow during normal gait  

Microsoft Academic Search

The study purpose was to estimate the ability of joint moments to transfer mechanical energy through the leg and trunk during gait. A segmental power analysis of five healthy adult subjects revealed that internal joint extensor moments removed energy from the leg and added energy to the trunk, while flexor moments and gravity produced the opposite effects. The only exception

Karen Lohmann Siegel; Thomas M Kepple; Steven J Stanhope

2004-01-01

351

Can Strength Training Predictably Improve Gait Kinematics? A Pilot  

E-print Network

and Knee Extensor Strengthening on Lower- Extremity Alignment in Cerebral Palsy Diane L. Damiano, Allison S that excessive hip and knee flexion during gait, as frequently seen in ambulatory children with cerebral palsy on the effects of hip and knee extensor strength- ening on lower-extremity align- ment in cerebral palsy. Phys

Delp, Scott

352

Gait Classificaiton in Children with Cerebral Palsy by Bayesian Approach  

Microsoft Academic Search

Cerebral palsy (CP) is generally considered as a nonprogressive neuro-developmental condition that occurs in early childhood and is associated with a motor impairment, usually affecting mobility and posture. Automatic accurate identification of cerebral palsy gait has many potential applications, for example, assistance in diagnosis, clinical decisionmaking and communication among the clinical professionals. In previous studies, support vector machine (SVM) and

Bai-ling Zhang; Yanchun Zhang; Tuan D. Pham; Rezaul K. Begg

2007-01-01

353

Human Identification using Gait and Face Rama Chellappa  

E-print Network

and measured when the subject is far away from the camera is human gait or the style of walking. For optimal performance, the system must use as many cues as possible and combine them in meaningful ways. Information may (data fusion) or each signal/feature can be matched separately, using pos- sibly different techniques

Zhu, Zhigang

354

The effect of divided attention on gait stability following concussion  

Microsoft Academic Search

Background. The need to identify functional impairment following a brain injury is critical to prevent re-injury during the period of recovery. While many neuropsychological tests have been developed to assess cognitive performance, relatively little information on gait and dynamic stability is available on motor task performance for young adults following concussion. This study was per- formed to investigate the effect

Tonya M. Parker; Louis R. Osternig; Heng-Ju Lee; Paul van Donkelaar; Li-Shan Chou

355

Bill Goodwine and Joel Burdick Gait Controllability for Legged Robots  

E-print Network

Bill Goodwine and Joel Burdick Gait Controllability for Legged Robots Bill Goodwine Joel Burdick to the legged case, where the relevant mechanics are not smooth. #12;Bill Goodwine and Joel Burdick Introduction to a class of nonsmooth systems we call stratified. #12;Bill Goodwine and Joel Burdick Stratified Control

Goodwine, Bill

356

Gait analysis in patients with a preformed articulated knee spacer  

Microsoft Academic Search

Two-stage revision is one of the most widely accepted procedures to eradicate infection and restore function in infected knee prosthesis; while the use of an articulated spacers is advocated by many as a means to preserve function between stages, no data are available regarding gait parameters after spacer implant. The aim of present study was to assess and compare the

N. Logoluso; C. Champlon; G. Melegati; F. Dell'Oro; C. L. Romanò

357

Comparative gait analysis of two strains of turkey, meleagris gallopavo  

Microsoft Academic Search

1. Economic requirements have encouraged farmers to select broad?breasted strains of turkeys (Meleagris gallopavo). These birds are very heavy (more than 30 kg), have pectoral hypertrophy and are frequently lame. Traditional turkeys, closer to wild birds, weigh 9 kg on average.2. Gaits, which are motor pattern expressions, seem to be linked to species morphology. However, no significant differences are evident

A. Abourachid

1991-01-01

358

Fusion of Face and Gait for Automatic Human Recognition  

Microsoft Academic Search

In recent years, several techniques have been proposed which integrate face, a physical biometric, with gait, a behavioral biometric, with the aim of investigating if such a combination will improve upon the performance of methods which exclusively employ only one of these biometrics. An overview of some of the well-known approaches in this area, along with a discussion of the

Rabia Jafri; Hamid R. Arabnia

2008-01-01

359

Biomechanical Modelling of Phase Transitions for Human Gait Javier Finat  

E-print Network

Biomechanical Modelling of Phase Transitions for Human Gait Javier Finat Dept. of Algebra, Faculty- pensatory behaviours. 2 Introduction Biomechanics has an increasing influence in medi- cal areas related to physiology, pathology and clin- ical treatment. Research in orthopaedic and injury biomechanics for disabled

Llanos, Diego R.

360

Department of Bioengineering Spring 2013 Gait Simulator for Prosthetic Feet  

E-print Network

PENNSTATE Department of Bioengineering Spring 2013 Gait Simulator for Prosthetic Feet Overview during use. Investigating the cause of failure is important in helping to make both types of feet more of both the Jaipur and Polyurethane feet to gain a better understanding of where pressure builds up

Demirel, Melik C.

361

Gait characteristics following Achilles tendon elongation: the foot rocker perspective  

Microsoft Academic Search

The action of three functional rockers, namely the heel, ankle and forefoot rocker, assist the progression of the leg over the support- ing foot. The purpose of this case series was to analyze the occurrence of foot rockers during gait in three children with cerebral palsy (CP) who had undergone the tendo-Achilles lengthening (TAL), procedure followed by a clinic- or

TADEUSZ BOBER; ALICJA DZIUBA; KRYSTYNA KOBEL-BUYS; KORNELIA KULIG

2008-01-01

362

White matter microstructural organization and gait stability in older adults.  

PubMed

Understanding age-related decline in gait stability and the role of alterations in brain structure is crucial. Here, we studied the relationship between white matter microstructural organization using Diffusion Tensor Imaging (DTI) and advanced gait stability measures in 15 healthy young adults (range 18-30 years) and 25 healthy older adults (range 62-82 years). Among the different gait stability measures, only stride time and the maximum Lyapunov exponent (which quantifies how well participants are able to attenuate small perturbations) were found to decline with age. White matter microstructural organization (FA) was lower throughout the brain in older adults. We found a strong correlation between FA in the left anterior thalamic radiation and left corticospinal tract on the one hand, and step width and safety margin (indicative of how close participants are to falling over) on the other. These findings suggest that white matter FA in tracts connecting subcortical and prefrontal areas is associated with the implementation of an effective stabilization strategy during gait. PMID:24959139

Bruijn, Sjoerd M; Van Impe, Annouchka; Duysens, Jacques; Swinnen, Stephan P

2014-01-01

363

Wavelet applications to kinematic and EMG signals in gait analysis  

Microsoft Academic Search

The main objectives of the research was to (1) demonstrate the superiority of the wavelet transform over conventional signal processing techniques in processing kinematic and EMG signals, (2) determining a way to assess physiological behavior of neuromuscular transmissions, (3) providing accurate three dimensional angular description of the lower extremity behavior during human gait, and (4) providing stable and accurate frequency

Adham Rashad Ismail

1998-01-01

364

Modeling and gait design of a 6-tetrahedron walker robot  

Microsoft Academic Search

This work describes the use of simulating walker robots to design choreographed gaits for a tetrahedral (TET) walker robot. A TET robot is composed of nodes and struts arranged into tetrahedral cells. The extension and contraction of the struts allows the tetrahedral robot to walk. The Hope College Controls Team so far has built a working 4-TET robot and has

Miguel Abrahantes; Leif Nelson; Peter Doorn

2010-01-01

365

Genetic Algorithms for Gait Synthesis in a Hexapod Robot  

E-print Network

and George A. Bekey Institute for Robotics and Intelligent Systems and Center for Neural Engineering and control of the sequences of leg movements representing specific gait patterns. In many animals easily rep- resent the periodic sequences seen in all forms of animal and machine walking. Once

Portland State University

366

GA-BASED GAIT GENERATION OF SONY QUADRUPED ROBOTS  

Microsoft Academic Search

This paper presents a GA (Genetic Algorithm) approach to the development of locomotion gait for Sony quadruped robots. The selection of GA parameters such as the population size and recombination methods is made to be flexible and strive towards optimal performance autonomously. An interactive software environment with an overhead CCD camera is used to evaluate the performance of the generated

Dragos Golubovic; Huosheng Hu

2003-01-01

367

A novel approach for assessing gait using foot mounted accelerometers  

Microsoft Academic Search

Accelerometer technology is becoming increasingly smaller and cheaper to develop. As a result such devices can easily be integrated into a shoe to ubiquitously capture gait information which could potentially be used to detect development of injuries, neuro-degenerative diseases or a change in disease symptoms. Much research has been done in the past comparing accelerometer data to kinematic or spatio-temporal

Matt Patterson; Brian Caulfield

2011-01-01

368

Connectivity of the pedunculopontine nucleus in parkinsonian freezing of gait  

E-print Network

(FOG) patients, compared with non-FOG PD and healthy controls using diffusion tensor imaging techniques showed connectivity with the cerebellum in controls and non-FOG PD. FOG patients showed absence the connectivity of the PPN freezing of gait (FOG) patients, compared with non-FOG PD and healthy controls. Methods

Hansen, Peter

369

Biomechanical analysis of gait adaptation in the nematode Caenorhabditis elegans  

E-print Network

,c , and Aravinthan D. T. Samuela,2 a Department of Physics and Center for Brain Science, Harvard University in viscosity. In these fluids, the worm undulatory gait varies continuously with changes in external load viscoelastic properties of the worm's body and their role in locomotory dynamics. We incor- porate muscle

370

When does a gait transition occur during human locomotion?  

Microsoft Academic Search

When a treadmill accelerates continuously, the walk-run transi- tion has generally been assumed to occur at the instant when a flight phase is first observed, while the run-walk transition has been assumed to occur at the instant of the first double support period. There is no theoretical or empirical evidence to suggest that gait transitions occur at the instant of

Alan Hreljac; Rodney T. Imamura; Rafael F. Escamilla; W. Brent Edwards

2007-01-01

371

Validation of an ear-worn sensor for gait monitoring using a force-plate instrumented treadmill.  

PubMed

A force-plate instrumented treadmill (Hp Cosmos Gaitway) was used to validate the use of a miniaturised lightweight ear-worn sensor (7.4 g) for gait monitoring. Thirty-four healthy subjects were asked to progress up to their maximum walking speed on the treadmill (starting at 5 km/h, with 0.5 km increments). The sensor houses a 3D accelerometer which measures medio-lateral (ML), vertical (VT) and anterior-posterior (AP) acceleration. Maximum signal ranges and zero crossings were derived from accelerometer signals per axis, having corrected for head motion and signal noise. The maximal force, measured by the instrumented treadmill correlated best with a combination of VT and AP acceleration (R-squared = 0.36, p = 0), and combined VT, ML, and AP acceleration (R-squared=0.36, p = 0). Weight-acceptance peak force and impulse values also correlated well with VT and AP acceleration (Weight acceptance: R-squared = 0.35, p = 0, Impulse: 0.26, p = 0), and combined VT, ML, and AP acceleration (Weight acceptance: R-squared = 0.35, p = 0, Impulse: 0.26, p=0). Zero crossing features on the ML axis provided an accurate prediction of the gait-cycle, with a mean difference of 0.03s (-0.01, 0.05 confidence intervals). PMID:22169386

Atallah, Louis; Wiik, Anatole; Jones, Gareth G; Lo, Benny; Cobb, Justin P; Amis, Andrew; Yang, Guang-Zhong

2012-04-01

372

Influence of pressure-relief insoles developed for loaded gait (backpackers and obese people) on plantar pressure distribution and ground reaction forces.  

PubMed

The aims of this study were to test the effects of two pressure relief insoles developed for backpackers and obese people on the ground reaction forces (GRF) and plantar pressure peaks during gait; and to compare the GRF and plantar pressures among normal-weight, backpackers, and obese participants. Based on GRF, plantar pressures, and finite element analysis two insoles were manufactured: flat cork-based insole with (i) corkgel in the rearfoot and forefoot (SLS1) and with (ii) poron foam in the great toe and lateral forefoot (SLS2). Gait data were recorded from 21 normal-weight/backpackers and 10 obese participants. The SLS1 did not influence the GRF, but it relieved the pressure peaks for both backpackers and obese participants. In SLS2 the load acceptance GRF peak was lower; however, it did not reduce the plantar pressure peaks. The GRF and plantar pressure gait pattern were different among the normal-weight, backpackers and obese participants. PMID:24468683

Peduzzi de Castro, Marcelo; Abreu, Sofia; Pinto, Viviana; Santos, Rubim; Machado, Leandro; Vaz, Mario; Vilas-Boas, João Paulo

2014-07-01

373

Early presentation of gait impairment in Wolfram Syndrome  

PubMed Central

Background Classically characterized by early onset insulin-dependent diabetes mellitus, optic atrophy, deafness, diabetes insipidus, and neurological abnormalities, Wolfram syndrome (WFS) is also associated with atypical brainstem and cerebellar findings in the first decade of life. As such, we hypothesized that gait differences between individuals with WFS and typically developing (TD) individuals may be detectable across the course of the disease. Methods Gait was assessed for 13 individuals with WFS (min 6.4?yrs, max 25.8?yrs) and 29 age-matched, typically developing individuals (min 5.6?yrs, max 28.5?yrs) using a GAITRite ® walkway system. Velocity, cadence, step length, base of support and double support time were compared between groups. Results Across all tasks, individuals with WFS walked slower (p = 0.03), took shorter (p ? 0.001) and wider (p ? 0.001) steps and spent a greater proportion of the gait cycle in double support (p = 0.03) compared to TD individuals. Cadence did not differ between groups (p = 0.62). Across all tasks, age was significantly correlated with cadence and double support time in the TD group but only double support time was correlated with age in the WFS group and only during preferred pace forward (rs= 0.564, p = 0.045) and dual task forward walking (rs= 0.720, p = 0.006) tasks. Individuals with WFS also had a greater number of missteps during tandem walking (p ? 0.001). Within the WFS group, spatiotemporal measures of gait did not correlate with measures of visual acuity. Balance measures negatively correlated with normalized gait velocity during fast forward walking (rs = ?0.59, p = 0.03) and percent of gait cycle in double support during backward walking (rs = ?0.64, p = 0.03). Conclusions Quantifiable gait impairments can be detected in individuals with WFS earlier than previous clinical observations suggested. These impairments are not fully accounted for by the visual or balance deficits associated with WFS, and may be a reflection of early cerebellar and/or brainstem abnormalities. Effective patient-centered treatment paradigms could benefit from a more complete understanding of the progression of motor and other neurological symptom presentation in individuals with WFS. PMID:23217193

2012-01-01

374

How do alternative bearing surfaces influence wear behavior?  

PubMed

Metal, ceramic, and polyethylene liners represent contemporary bearing choices for total joint replacement. Each has limitations in terms of design, sensitivity to manufacturing, and surgical placement. With polyethylene, larger femoral heads represent a design restriction and a potential wear issue. One side benefit is that polyethylene does not click, squeak, or create stripe wear. The attraction of hard-on-hard bearings (metal-on-metal, ceramic-on-ceramic) is that their typically ultra-low wear alleviates concerns with large femoral head designs. However, hard-on-hard bearings produce stripe wear due to the effects of the rigid liner edge. Slight subluxation (microseparation) during swing phase of gait can result in stripe wear on the ball and liner rim. In addition, high levels of implant wear with vertically placed cups can be anticipated. Currently, only alumina-on-alumina bearings can claim virtually no biologic risk. Thus, the role of laboratory studies is to isolate relevant aspects of performance by cup design and to predict the risk-benefit ratios in patients requiring total hip replacement. PMID:18612022

Clarke, Ian C; Manley, Michael T

2008-01-01

375

Bearing fatigue investigation 3  

NASA Technical Reports Server (NTRS)

The operating characteristics of large diameter rolling-element bearings in the ultra high speed regimes expected in advanced turbine engines for high performance aircraft were investigated. A high temperature lubricant, DuPont Krytox 143 AC, was evaluated at bearing speeds to 3 million DN. Compared to the results of earlier, similar tests using a MIL-L-23699 (Type II) lubricant, bearings lubricated with the high density Krytox fluid showed significantly higher power requirements. Additionally, short bearing lives were observed when this fluid was used with AISI M50 bearings in an air atmosphere. The primary mode of failure was corrosion initiated surface distress (fatigue) on the raceways. The potential of a case-carburized bearing to sustain a combination of high-tangential and hertzian stresses without experiencing race fracture was also investigated. Limited full scale bearing tests of a 120 mm bore ball bearing at a speed of 25,000 rpm (3 million DN) indicated that a carburized material could sustain spalling fatigue without subsequent propagation to fracture. Planned life tests of the carburized material had to be aborted, however, because of apparent processing-induced material defects.

Nahm, A. H.; Bamberger, E. N.; Signer, H. R.

1982-01-01

376

Bearing servicing tool  

NASA Technical Reports Server (NTRS)

A tool for removing and/or replacing bearings in situ is presented. The tool is comprised of a brace having a first end adapted to engage a first end of the bearing housing, and a second end adapted to engage a second end of the bearing housing. If the two ends of the bearing housing are different in configuration, then the respective ends of the brace are configured accordingly. An elongate guide member integral with the brace has two parts, each projecting endwise from a respective end of the brace. A removable pressure plate can be mounted on either part of the guide member for longitudinal movement therealong and has first and second ends of different configurations adapted to engage the first and second ends of the bearing. A threaded-type drive is cooperative between the guide and the pressure plate to move the pressure plate longitudinally along the guide and apply a force to the bearing, either to remove the bearing from its housing, or to emplace a new bearing in the housing.

Boyce, Rex A. (inventor)

1992-01-01

377

Bearing Thermal Performance Prediction  

NASA Technical Reports Server (NTRS)

Parameter called lubricant percent volume or cavity factor (XCAV) used primarily in calculation of ball or roller drag and, therefore, significantly affects calculated bearing-heat generation and temperature distribution. New equation accounts for sensitivity of XCAV to shaft speed, lubricant flow rate, and bearing size, and provides significant improvement over previous estimation methods.

Parker, R. J.

1986-01-01

378

Grizzly bears and forestry  

Microsoft Academic Search

We assessed the occurrence and fruit production of 13 grizzly bear foods in west-central Alberta, Canada, to better understand use of clearcuts by grizzly bears. Comparisons were made between clearcuts and upland forest stands, while specific models describing food or fruit occurrence within clearcuts were developed from canopy, clearcut age, scarification, and terrain-related variables using logistic regression. Ants, Equisetum spp.,

S. E. Nielsen; R. H. M. Munro; E. L. Bainbridge; G. B. Stenhouse; M. S. Boyce

2004-01-01

379

Linear kinematic air bearing  

NASA Technical Reports Server (NTRS)

Bearing provides continuous, smooth movement of the cat's-eye mirror, eliminating wear and deterioration of bearing surface and resulting oscillation effects in servo system. Design features self-aligning configuration; single-point, pivotal pad mounting, having air passage through it; and design of pads that allows for precise control of discharge path of air from pads.

Mayall, S. D.

1974-01-01

380

Hollow rolling element bearings  

NASA Technical Reports Server (NTRS)

A low mass rolling element with a lightweight core and hollow center was developed for use in bearings. The core is plated so as to provide a hard surface and increase the life and reliability of the high speed ball bearings.

Parker, R. J. (inventor)

1973-01-01

381

Quantitative evaluation of the major determinants of human gait.  

PubMed

Accurate knowledge of the isolated contributions of joint movements to the three-dimensional displacement of the center of mass (COM) is fundamental for understanding the kinematics of normal walking and for improving the treatment of gait disabilities. Saunders et al. (1953) identified six kinematic mechanisms to explain the efficient progression of the whole-body COM in the sagittal, transverse, and coronal planes. These mechanisms, referred to as the major determinants of gait, were pelvic rotation, pelvic list, stance knee flexion, foot and knee mechanisms, and hip adduction. The aim of the present study was to quantitatively assess the contribution of each major gait determinant to the anteroposterior, vertical, and mediolateral displacements of the COM over one gait cycle. The contribution of each gait determinant was found by applying the concept of an 'influence coefficient', wherein the partial derivative of the COM displacement with respect to a prescribed determinant was calculated. The analysis was based on three-dimensional measurements of joint angular displacements obtained from 23 healthy young adults walking at slow, normal and fast speeds. We found that hip flexion, stance knee flexion, and ankle-foot interaction (comprised of ankle plantarflexion, toe flexion and the displacement of the center of pressure) are the major determinants of the displacements of the COM in the sagittal plane, while hip adduction and pelvic list contribute most significantly to the mediolateral displacement of the COM in the coronal plane. Pelvic rotation and pelvic list contribute little to the vertical displacement of the COM at all walking speeds. Pelvic tilt, hip rotation, subtalar inversion, and back extension, abduction and rotation make negligible contributions to the displacements of the COM in all three anatomical planes. PMID:24582352

Lin, Yi-Chung; Gfoehler, Margit; Pandy, Marcus G

2014-04-11

382

Voluntary toe-walking gait initiation: electromyographical and biomechanical aspects.  

PubMed

This study was carried out to investigate the biomechanical constraints of toe-walking gait initiation and the associated changes in motor program compared to the well documented heel-toe walking gait initiation. Seven healthy subjects volunteered for this study. Gait was initiated on a force platform, at three self-selected speed conditions, from an erect spontaneous posture in the control situation (CS) and from a posture with heels raised in the test situation (TS). Surface electromyographical (EMG) activities of muscles soleus (Sol) and tibialis anterior (TA) were recorded on both limbs. We analysed the consequences of the heel-off posture on EMG patterns and biomechanical activities. Whatever the speed condition, the centre of foot pressure was initially located more ahead of the ankle axis in TS than in CS, with an increased Sol and TA EMG activity. The EMG pattern which expresses the motor program governing gait initiation was modified in TS in comparison to CS and induced adaptations of the anticipatory postural adjustments (APA) that precede toe-off of the stepping limb. A lengthening of the APA duration allowed the subjects in TS to reach a gait velocity similar to the one obtained in CS at the end of the anticipatory movements and also at the end of the first step. In TS, the velocity of the centre of gravity at time of toe-off covaried, as in CS, with CG velocity at the end of the first step, still resulting from TA muscular actions during the APA but also probably from other combined muscular actions. PMID:12428139

Couillandre, Annabelle; Maton, Bernard; Brenière, Yvon

2002-12-01

383

Antident Bearing-Ball Retainer  

NASA Technical Reports Server (NTRS)

Jig prevents indentation of bearing balls by hard contact with edges of inner bearing rings during assembly. Jig is retaining ring which includes fingers that separates balls and pushes them against outer bearing and out of contact with inner bearing rings. Eliminates need for ball-retaining tabs on bearing cage.

Thomas, Larry L., Jr.

1995-01-01

384

Arcturus and the Bears  

NASA Astrophysics Data System (ADS)

Arcturus is the brightest star in Bootes. The ancient Greek name Arktouros means Bear Guard. The star, however, is not close to Ursa Maior (Big She-Bear) and Ursa Minor (Little She-Bear), as the name would suggest. This curious discrepancy could be explained by the star proper motion, assuming the name Bear Guard is a remote cultural heritage. The proper motion analysis could allow us to get an insight also into an ancient myth regarding Ursa Maior. Though we cannot explain scientifically such a myth, some interesting suggestions can be obtained about its possible origin, in the context of the present knowledge of the importance of the cult of the bear both during the Palaeolithic times and for several primitive populations of modern times, as shown by the ethnological studies.

Antonello, E.

2009-08-01

385

Study of Catcher Bearings for High Temperature Magnetic Bearing Application  

E-print Network

temperature permanent magnet based magnetic bearings. The magnetic bearings are made of high temperature resistant permanent magnets (up to 1000 degrees F). A test rig has been developed to test these magnetic bearings. The test rig mainly consists of two...

Narayanaswamy, Ashwanth

2011-08-08

386

Abstract --The Robotic Gait Rehabilitation (RGR) Trainer, was designed and built to target secondary gait deviations in  

E-print Network

patterns of both the affected and unaffected limbs. Asymmetry of stance time during gait, a common feature is 0.5 m/s which is less than half of that seen in healthy subjects (1.52 m/s) [5, 6]. Asymmetries mark post- stroke ambulation, which are caused in part by weakness in the affected limb and abnormal synergy

Mavroidis, Constantinos

387

Conceptual Design and Feasibility of Foil Bearings for Rotorcraft Engines: Hot Core Bearings  

NASA Technical Reports Server (NTRS)

Recent developments in gas foil bearing technology have led to numerous advanced high-speed rotating system concepts, many of which have become either commercial products or experimental test articles. Examples include oil-free microturbines, motors, generators and turbochargers. The driving forces for integrating gas foil bearings into these high-speed systems are the benefits promised by removing the oil lubrication system. Elimination of the oil system leads to reduced emissions, increased reliability, and decreased maintenance costs. Another benefit is reduced power plant weight. For rotorcraft applications, this would be a major advantage, as every pound removed from the propulsion system results in a payload benefit.. Implementing foil gas bearings throughout a rotorcraft gas turbine engine is an important long-term goal that requires overcoming numerous technological hurdles. Adequate thrust bearing load capacity and potentially large gearbox applied radial loads are among them. However, by replacing the turbine end, or hot section, rolling element bearing with a gas foil bearing many of the above benefits can be realized. To this end, engine manufacturers are beginning to explore the possibilities of hot section gas foil bearings in propulsion engines. This overview presents a logical follow-on activity by analyzing a conceptual rotorcraft engine to determine the feasibility of a foil bearing supported core. Using a combination of rotordynamic analyses and a load capacity model, it is shown to be reasonable to consider a gas foil bearing core section. In addition, system level foil bearing testing capabilities at NASA Glenn Research Center are presented along with analysis work being conducted under NRA Cooperative Agreements.

Howard, Samuel A.

2007-01-01

388

Weight Management  

MedlinePLUS

... weight... Read full story >> Healthy Weight Loss share Body Image: It's Not Just About How You See Your ... your own skin share The ABC's of Positive Body Image Feeling comfortable in your own skin can be ...

389

Weight Control  

MedlinePLUS

... obese. Achieving a healthy weight can help you control your cholesterol, blood pressure and blood sugar. It ... use more calories than you eat. A weight-control strategy might include Choosing low-fat, low-calorie ...

390

Sensitivity of spatiotemporal gait parameters in measuring disease severity in friedreich ataxia.  

PubMed

Friedreich ataxia (FRDA) is an autosomal recessive disease with gait ataxia being the main source of morbidity. Mobility progressively declines, from initial symptom onset at approximately 10-15 years of age to being unable to ambulate 10-15 years later. Here, we sought to investigate the relationship between spatiotemporal gait parameters and clinical markers of disease severity. Thirteen people with FRDA walked along an 8.3-m GAITRite® mat six times each at their preferred fast and slow speeds. Relationships between spatiotemporal gait parameters and a range of clinical and disease characteristics were examined. Significant correlations were found between spatiotemporal gait characteristics at each of the walking speeds and Friedreich Ataxia Rating Scale (FARS) score and disease duration. During the fast-walking condition, gait speed and cadence decreased with an increase in disease duration and the FARS score. GAA1 repeat expansion negatively correlated with double-support percentage of the gait cycle in all speed conditions demonstrating a relationship between the genetic mutation and compensatory strategies for impaired dynamic balance. In all speed conditions, there were correlations between a range of spatiotemporal gait characteristics and the timed 25-ft walk test, a well-established measure of gait mobility. These findings suggest that spatiotemporal gait parameters are a sensitive measure of gait decline in individuals with FRDA and should be considered for inclusion in intervention studies whilst participants are still ambulant. PMID:25022367

Milne, Sarah C; Hocking, Darren R; Georgiou-Karistianis, Nellie; Murphy, Anna; Delatycki, Martin B; Corben, Louise A

2014-12-01

391

Stumbling with optimal phase reset during gait can prevent a humanoid from falling.  

PubMed

The human biped walking shows phase- dependent transient changes in gait trajectory in response to external brief force perturbations. Such responses, referred to as the stumbling reactions, are usually accompanied with phase reset of the walking rhythm. Our previous studies provided evidence, based on a human gait experiment and analyses of mathematical models of gait in the sagittal plane, that an appropriate amount of phase reset in response to a perturbation depended on the gait phase at the perturbation and could play an important role for preventing the walker from a fall, thus increasing gait stability. In this paper, we provide a further material that supports this evidence by a gait experiment on a biped humanoid. In the experiment, the impulsive force perturbations were applied using push-impacts by a pendulum-like hammer to the back of the robot during gait. The responses of the external perturbations were managed by resetting the gait phase with different delays or advancements. The results showed that appropriate amounts of phase resetting contributed to the avoidance of falling against the perturbation during the three-dimensional robot gait. A parallelism with human gait stumbling reactions was discussed. PMID:16969676

Nakanishi, Masao; Nomura, Taishin; Sato, Shunsuke

2006-11-01

392

Gait in amyotrophic lateral sclerosis: Is gait pattern differently affected in spinal and bulbar onset of the disease during dual task walking?  

PubMed

Abstract Amyotrophic lateral sclerosis (ALS) is characterized by weakness, fatigue, loss of balance and coordination. The purpose of the study was to examine gait in ALS patients. Gait was compared in ALS with spinal and bulbar onset, while performing dual mental and motor tasks. Dual-task walking was performed by 27 ALS patients, 13 with spinal- and 14 with bulbar-onset disease. Twenty-nine healthy subjects were used as a control group. The subjects performed a basic, simple walking task, dual-motor task, dual-mental task, and combined motor and mental tasks. Results showed that dual-task paradigm has an effect on gait in ALS patients. Gait was differently affected in spinal and bulbar onset of ALS by some of the given tasks. Mental tasks had a larger effect than motor tasks in all gait parameters. In conclusion, both ALS forms have impaired gait in dual tasks. Simple walk in patients with spinal onset shows higher variability of certain gait parameters compared to bulbar-onset patients and controls. Differences in gait could also indicate postural instability and possible falls in complex walking situations. PMID:24918304

Radovanovi?, Sasa; Mili?ev, Milena; Peri?, Stojan; Basta, Ivana; Kosti?, Vladimir; Stevi?, Zorica

2014-12-01

393

Ball Bearing Mechanics  

NASA Technical Reports Server (NTRS)

Load-deflection relationships for different types of elliptical contacts such as those found in a ball bearing are developed. Simplified expressions that allow quick calculations of deformation to be made simply from a knowledge of the applied load, the material properties, and the geometry of the contacting elements are presented. Ball bearings subjected to radial, thrust and combined ball loads are analyzed. A design criterion for fatigue life of ball bearings is developed. The section of a satisfactory lubricant, as well as describing systems that provide a constant flow of lubricant to the contact, is considered.

Hamrock, B. J.; Dowson, D.

1981-01-01

394

Serial assessments to determine normalization of gait following anterior cruciate ligament reconstruction.  

PubMed

There is an increased emphasis to identify clinically applicable methods that quantify gait deficits following anterior cruciate ligament reconstruction (ACLR). The purpose of this study was to perform serial gait assessments in a clinical setting to determine whether and when clinical gait parameters normalize in patients following ACLR. The hypothesis was that a clinically available gait treadmill would quantify gait deficits measured at 4 weeks post-reconstruction. The secondary hypothesis was that patients would demonstrate incremental improvements in these gait parameters measured at each interval up to 12 weeks post-reconstruction, and that the objectively measured improvements would correlate to the patient's subjective rating of function. Fifteen subjects, five male and 10 female, who had initial unilateral anterior cruciate ligament injury were selected for this study on the basis of operative data. All subjects were evaluated in a physical therapy clinic within 3 days following ACLR and were enrolled in a standardized rehabilitation program. The dependent gait variables of step length, stance time and gait velocity were measured at 4, 6, 8 and 12 weeks post-ACLR on a commercially available gait treadmill. A 2 x 4 multivariate analysis of variance (2 within factors) with measures for limb involvement (uninvolved and involved) and repeated measures for time (4, 6, 8 and 12 weeks) was used to assess the interactions and the main effects on the gait variables of stance time and step length. The results of this study supported the hypothesis that gait deficits and serial improvements can be objectively quantified in a clinical setting (P<0.001). Specifically, stance time, step length and gait velocity deficits evaluated at 4 weeks showed significant improvements at the measured intervals. Step length normalized at week 8. Stance time and gait velocity reached normal levels at the 12-week time interval. Subjective activity of daily living scores (ADLS) also improved following the 12-week rehabilitation, from 53+/-17% to a mean score of 88+/-11% (P<0.001). ADLS scores significantly correlated to step length (R=0.63) and stance time (R=0.53) in the involved limb. Self-selected gait velocity also correlated to ADLS scores and significantly predicted 49% of the variance in the subjective outcome measure. A clinically available gait treadmill can be used to quantify gait deficits and improvements following ACLR. Serial assessments of walking gait may aid clinicians to identify and target deficits in their patients during rehabilitation. PMID:18510594

Minning, S J; Myer, G D; Mangine, R E; Eifert-Mangine, M; Colosimo, A J

2009-08-01

395

Size and growth patterns of the Yellowstone grizzly bear  

USGS Publications Warehouse

Weights and/or measurements of 151 grizzly bears (Ursus arctos) captured 261 times were recorded from 1975 to 1985. Males were consistently heavier than females within all age classes beginning at age 2. Mean weight for 65 captive males (5+ years old) was 192 kg and 135 kg for 63 adult females (5+ years old). Mean monthly weights by sex and age class indicated adults lost weight from den emergence through July, generally regaining emergence weight by August. Weaned yearlings lost weight July-Septmber, whereas unweaned yearlings gained weight during the same period. Sexual dimorphism in body measurements within age classes was apparent in cubs and became significant in all body measurements by age 3. Girth was the measurement most closely correlated with weight for both males and females. Adults feeding at garbage dumps weighted more than bears relying on natural food sources. Bears were smaller and weighed less in this study than during the period 1959-70, when major dumps were available as a food source. Mean annual weights of nondump females were highly correlated with annual habitat productivity indices for Yellowstone Park. Correlations between mean adult female weight an cub litter size (r) = 0.92) and mean age at 1st cub production (r = -0.52) were apparent. In general, females with reliable high-energy foods tended to attain larger body sizes, mature at an earlier age, and have larger cub litters than females using relatively low-energy foods.

Blanchard, Bonnie M.

1987-01-01

396

Hydrostatic bearing support  

NASA Technical Reports Server (NTRS)

A hydrostatic bearing support system is provided which comprises a bearing housing having a polygonally configured outer surface which defines at least three symmetrically disposed working faces and a plurality of pressure plates, each of which is disposed relatively opposite a corresponding working face and spaced therefrom to define a gap therebetween. A hydrostatic support film is created in the gap for supporting the housing in spaced relationship to the pressure plates.

Cunningham, R. E. (inventor)

1977-01-01

397

Nanoprecipitation in bearing steels  

Microsoft Academic Search

?-phase is the main hardening species in bearing steels and appears in both martensitically and bainitically hardened microstructures. This work presents a survey of the microstrucural features accompanying nanoprecipitation in bearing steels. Nanoprecipitate structures formed in 1C–1.5Cr wt.% with additions of Cr, Mn, Mo, Si and Ni are studied. The work is combined with thermodynamic calculations and neural networks to

A. T. W. Barrow; P. E. J. Rivera-Díaz-del-Castillo

2011-01-01

398

21 CFR 105.66 - Label statements relating to usefulness in reducing or maintaining body weight.  

Code of Federal Regulations, 2012 CFR

...usefulness in reducing or maintaining body weight. 105.66 Section 105.66...usefulness in reducing or maintaining body weight. (a) General requirements...usefulness in reducing or maintaining body weight shall bear: (1)...

2012-04-01

399

21 CFR 105.66 - Label statements relating to usefulness in reducing or maintaining body weight.  

...usefulness in reducing or maintaining body weight. 105.66 Section 105.66...usefulness in reducing or maintaining body weight. (a) General requirements...usefulness in reducing or maintaining body weight shall bear: (1)...

2014-04-01

400

21 CFR 105.66 - Label statements relating to usefulness in reducing or maintaining body weight.  

Code of Federal Regulations, 2010 CFR

...usefulness in reducing or maintaining body weight. 105.66 Section 105.66...usefulness in reducing or maintaining body weight. (a) General requirements...usefulness in reducing or maintaining body weight shall bear: (1)...

2010-04-01

401

21 CFR 105.66 - Label statements relating to usefulness in reducing or maintaining body weight.  

Code of Federal Regulations, 2013 CFR

...usefulness in reducing or maintaining body weight. 105.66 Section 105.66...usefulness in reducing or maintaining body weight. (a) General requirements...usefulness in reducing or maintaining body weight shall bear: (1)...

2013-04-01

402

21 CFR 105.66 - Label statements relating to usefulness in reducing or maintaining body weight.  

Code of Federal Regulations, 2011 CFR

...usefulness in reducing or maintaining body weight. 105.66 Section 105.66...usefulness in reducing or maintaining body weight. (a) General requirements...usefulness in reducing or maintaining body weight shall bear: (1)...

2011-04-01

403

Mechanical loading with or without weight-bearing activity: influence on bone strength index in elite female adolescent athletes engaged in water polo, gymnastics, and track-and-field.  

PubMed

Bone health is considered not to benefit from water-based sports because of their weight-supported nature, but available evidence primarily relies on DXA technology. Our purpose was to investigate musculoskeletal health in the upper and lower body in well-trained adolescent female athletes using pQCT and compare these athletes with less-active, age- and sex-matched peers. Bone mineral content, volumetric cortical and trabecular BMD, total and cortical area, and bone strength index were assessed at the distal and proximal tibia and radius in four groups of adolescent females (mean age, 14.9 years) including water polo players (n = 30), gymnasts (n = 25), track-and-field athletes (n = 34), and nonactive controls (n = 28). Water polo players did not show any benefit in bone strength index or muscle size in the lower leg when compared with controls. In contrast, gymnasts showed 60.1 % and 53.4 % greater bone strength index at the distal and proximal tibia, respectively, than nonactive females (p < 0.05). Similarly, track-and-field athletes displayed 33.9 % and 14.7 % greater bone strength index at the distal and proximal tibia, respectively, compared with controls (p < 0.05). In the upper body, water polo players had 31.9 % greater bone strength index at the distal radius, but not the radial shaft, and 15.2 % larger forearm muscle cross-sectional area than controls (p < 0.05). The greatest musculoskeletal benefits in the upper body were found in gymnasts. In conclusion, despite training at an elite level, female water polo players did not show any benefits in musculoskeletal health in the lower leg and only limited benefits in the upper body when compared with nonactive girls. PMID:22614913

Greene, David A; Naughton, Geraldine A; Bradshaw, Elizabeth; Moresi, Mark; Ducher, Gaele

2012-09-01

404

Contribution of brain imaging to the understanding of gait disorders in Alzheimer's disease: a systematic review.  

PubMed

Although gait disorders are common in Alzheimer's disease (AD), determining which brain structures and related lesions are specifically involved is a goal yet to be reached. Our objective was to systematically review all published data that examined associations between gait disorders and brain imaging in AD. Of 486 selected studies, 4 observational studies met the selection criteria. The number of participants ranged from 2 to 61 community dwellers (29%-100% female) with prodromal or dementia-stage AD. Quantitative gait disorders (ie, slower gait velocity explained by shorter stride length) were associated with white matter lesions, mainly in the medial frontal lobes and basal ganglia. The nigrostriatal dopamine system was unaffected. Qualitative gait disorders (ie, higher stride length variability) correlated with lower hippocampal volume and function. Gait disorders in AD could be explained by a high burden of age-related subcortical hyperintensities on the frontal-subcortical circuits (nonspecific) together with hippocampal atrophy and hypometabolism (specific). PMID:22930697

Annweiler, Cédric; Beauchet, Olivier; Celle, Sébastien; Roche, Frédéric; Annweiler, Thierry; Allali, Gilles; Bartha, Robert; Montero-Odasso, Manuel

2012-09-01

405

A block to pre-prepared movement in gait freezing, relieved by pedunculopontine nucleus stimulation  

PubMed Central

Gait freezing and postural instability are disabling features of Parkinsonian disorders, treatable with pedunculopontine nucleus stimulation. Both features are considered deficits of proximal and axial musculature, innervated predominantly by reticulospinal pathways and tend to manifest when gait and posture require adjustment. Adjustments to gait and posture are amenable to pre-preparation and rapid triggered release. Experimentally, such accelerated release can be elicited by loud auditory stimuli—a phenomenon known as ‘StartReact’. We observed StartReact in healthy and Parkinsonian controls. However, StartReact was absent in Parkinsonian patients with severe gait freezing and postural instability. Pedunculopontine nucleus stimulation restored StartReact proximally and proximal reaction times to loud stimuli correlated with gait and postural disturbance. These findings suggest a relative block to triggered, pre-prepared movement in gait freezing and postural instability, relieved by pedunculopontine nucleus stimulation. PMID:21705424

Thevathasan, Wesley; Pogosyan, Alek; Hyam, Jonathan A.; Jenkinson, Ned; Bogdanovic, Marko; Coyne, Terry J.; Silburn, Peter A.; Aziz, Tipu Z.

2011-01-01

406

Load responsive hydrodynamic bearing  

DOEpatents

A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

Kalsi, Manmohan S. (Houston, TX); Somogyi, Dezso (Sugar Land, TX); Dietle, Lannie L. (Stafford, TX)

2002-01-01

407

[Gait analysis--a prerequisite for general movement analysis].  

PubMed

Our system for analysis of gait is a combined visualisation of angular velocities in any joint with dynamic measurements of pressure at the sole while walking in a natural surrounding. Infrared reflectors are attached to chosen parts of the body. Their position in space is sampled over time and transferred to an easily manageable personal computer that visualizes motion in progression as angular velocities. Pressure at the sole is measured by pressure sensors. The magnitude of force is expressed as calibrated circular areas following the dynamic course of gait. The system is accurate and easily operated. The time necessary for measurements and evaluation of data as well as the costs render an application in daily clinical work acceptable. PMID:1462072

Kesselring, J; Calame, C; Zweifel, H J

1992-12-01

408

Effects of Pelvic Adjustment on Female University Students' Gait Variables  

PubMed Central

[Purpose] The purpose of this study was to examine the effects of pelvic adjustment using Gonstead techniques on posture in female university students. [Subjects] In this study, 30 female university students were selected and divided into a pelvic adjustment group of 15 subjects as an experimental group and a stretching group of 15 subjects as a control group. [Methods] Step length difference (SLD), stance phase difference (STPD), swing phase difference (SWPD), single support difference (SSD), and step time difference (STD) were evaluated in the subjects using an OptoGait. [Results] Whereas the adjustment group showed statistically significant differences in SLD, STPD, SWPD, SSD, and STD, the stretching group did not show any statistically significant differences in any of the items. [Conclusion] Pelvic adjustment can be applied using Gonstead techniques as a method of reducing differences in normal gait variables between the left and right sides in adults. PMID:24926147

Cho, Misuk; Jun, Ilsub

2014-01-01

409

Confronting Hip Resurfacing and Big Femoral Head Replacement Gait Analysis  

PubMed Central

Improved hip kinematics and bone preservation have been reported after resurfacing total hip replacement (THRS). On the other hand, hip kinematics with standard total hip replacement (THR) is optimized with large diameter femoral heads (BFH-THR). The purpose of this study is to evaluate the functional outcomes of THRS and BFH-THR and correlate these results to bone preservation or the large femoral heads. Thirty-one patients were included in the study. Gait speed, postural balance, proprioception and overall performance. Our results demonstrated a non-statistically significant improvement in gait, postural balance and proprioception in the THRS confronting to BFH-THR group. THRS provide identical outcomes to traditional BFH-THR. The THRS choice as bone preserving procedure in younger patients is still to be evaluated. PMID:24744841

Karampinas, Panagiotis K.; Evangelopoulos, Dimitrios S.; Vlamis, John; Nikolopoulos, Konstantinos; Korres, Dimitrios S.

2014-01-01

410

Gait event detection during stair walking using a rate gyroscope.  

PubMed

Gyroscopes have been proposed as sensors for ambulatory gait analysis and functional electrical stimulation systems. These applications often require detection of the initial contact (IC) of the foot with the floor and/or final contact or foot off (FO) from the floor during outdoor walking. Previous investigations have reported the use of a single gyroscope placed on the shank for detection of IC and FO on level ground and incline walking. This paper describes the evaluation of a gyroscope placed on the shank for determination of IC and FO in subjects ascending and descending a set of stairs. Performance was compared with a reference pressure measurement system. The absolute mean difference between the gyroscope and the reference was less than 45 ms for IC and better than 135 ms for FO for both activities. Detection success was over 93%. These results provide preliminary evidence supporting the use of a gyroscope for gait event detection when walking up and down stairs. PMID:24651724

Formento, Paola Catalfamo; Acevedo, Ruben; Ghoussayni, Salim; Ewins, David

2014-01-01

411

Multifractal detrended fluctuation analysis of human gait diseases  

PubMed Central

In this paper multifractal detrended fluctuation analysis (MFDFA) is used to study the human gait time series for normal and diseased sets. It is observed that long range correlation is primarily responsible for the origin of multifractality. The study reveals that the degree of multifractality is more for normal set compared to diseased set. However, the method fails to distinguish between the two diseased sets. PMID:24109454

Dutta, Srimonti; Ghosh, Dipak; Chatterjee, Sucharita

2013-01-01

412

Control engineering and electromyographic kinesiology analyses of normal human gait  

Microsoft Academic Search

:   In this study, we analyzed the electrical activity patterns of the antagonistic bi-articular and mono-articular muscles of\\u000a both legs during normal gait cycles, in terms of electromyographic (EMG) kinesiology and control engineering. For control\\u000a engineering analyses, we utilized a mechanical two-joint link model equipped with antagonistic pairs of bi-articular and mono-articular\\u000a muscles. It was confirmed that the coordinated activity

Fujio Hashimoto; Ryokei Ogawa; Osamu Kameyama

2000-01-01

413

Stability and Harmony of Gait in Children with Cerebral Palsy  

ERIC Educational Resources Information Center

The aim of this study was to quantitatively assess the stability and harmony of gait in children with cerebral palsy. Seventeen children with spastic hemiplegia due to cerebral palsy (5.0 [plus or minus] 2.3 years old) who were able to walk autonomously and seventeen age-matched children with typical development (5.7 [plus or minus] 2.5 years old,…

Iosa, Marco; Marro, Tiziana; Paolucci, Stefano; Morelli, Daniela

2012-01-01

414

Active Shape Model-Based Gait Recognition Using Infrared Images  

Microsoft Academic Search

\\u000a We present a gait recognition system using infra-red (IR) images. Since an IR camera is not affected by the intensity of illumination,\\u000a it is able to provide constant recognition performance regardless of the amount of illumination. Model-based object tracking\\u000a algorithms enable robust tracking with partial occlusions or dynamic illumination. However, this algorithm often fails in\\u000a tracking objects if strong edge

Daehee Kim; Seungwon Lee; Joonki Paik

2009-01-01

415

Anthropometric, gait and strength characteristics of Kenyan distance runners  

Microsoft Academic Search

This study intended to take a biomechanical approach to under- stand the success of Kenyan distance runners. Anthropometric, gait and lower extremity strength characteristics of six elite Kenyan distance runners were analyzed. Stride frequency, rela- tive stride length and ground contact time were measured at five running speeds (3.5 - 5.4 m\\/s) using a motion capture system. Isometric knee extension

Pui W. Kong; Hendrik de Heer

2008-01-01

416

Freezing of gait in patients with advanced Parkinson's disease  

Microsoft Academic Search

Summary.  \\u000a Background. Freezing of Gait (FOG) is one of the most disturbing and least understood symptom in advanced stage of Parkinson's disease\\u000a (PD). The contribution of the underlying pathological process and the antiparkinsonian treatment to the development of FOG\\u000a are controversial.\\u000a \\u000a \\u000a Objective. To study the relationships between clinical features of PD and therapeutic modalities in patients with advanced PD and

N. Giladi; T. A. Treves; E. S. Simon; H. Shabtai; Y. Orlov; B. Kandinov; D. Paleacu; A. D. Korczyn

2001-01-01

417

Effects of walking speed on asymmetry and bilateral coordination of gait.  

PubMed

The mechanisms regulating the bilateral coordination of gait in humans are largely unknown. Our objective was to study how bilateral coordination changes as a result of gait speed modifications during over ground walking. 15 young adults wore force sensitive insoles that measured vertical forces used to determine the timing of the gait cycle events under three walking conditions (i.e., usual-walking, fast and slow). Ground reaction force impact (GRFI) associated with heel-strikes was also quantified, representing the potential contribution of sensory feedback to the regulation of gait. Gait asymmetry (GA) was quantified based on the differences between right and left swing times and the bilateral coordination of gait was assessed using the phase coordination index (PCI), a metric that quantifies the consistency and accuracy of the anti-phase stepping pattern. GA was preserved in the three different gait speeds. PCI was higher (reduced coordination) in the slow gait condition, compared to usual-walking (3.51% vs. 2.47%, respectively, p=0.002), but was not significantly affected in the fast condition. GRFI values were lower in the slow walking as compared to usual-walking and higher in the fast walking condition (p<0.001). Stepwise regression revealed that slow gait related changes in PCI were not associated with the slow gait related changes in GRFI. The present findings suggest that left-right anti-phase stepping is similar in normal and fast walking, but altered during slow walking. This behavior might reflect a relative increase in attention resources required to regulate a slow gait speed, consistent with the possibility that cortical function and supraspinal input influences the bilateral coordination of gait. PMID:23680424

Plotnik, Meir; Bartsch, Ronny P; Zeev, Aviva; Giladi, Nir; Hausdorff, Jeffery M

2013-09-01

418

Application of Hybrid Multi-resolution Wavelet Decomposition Method in Detecting Human Walking Gait Events  

Microsoft Academic Search

Identifying walking gait events is important in gait analysis. In particular, heel-strike and toe-off are commonly used to define the stance phase and swing phase in normal human walking gait cycle. They are used to segment a stream of human motion data into discrete and meaningful sections that can be analyzed and compared with available literatures. This paper proposes multi-resolution

Darwin Gouwanda; S. M. N. Arosha Senanayake

2009-01-01

419

Influence of the instrumented force shoe on gait pattern in patients with osteoarthritis of the knee  

Microsoft Academic Search

Osteoarthritis (OA) of the knee is associated with alterations in gait. As an alternative to force plates, instrumented force\\u000a shoes (IFSs) can be used to measure ground reaction forces. This study evaluated the influence of IFS on gait pattern in patients\\u000a with knee OA. Twenty patients with knee OA walked in a gait laboratory on IFS and control shoes (CSs).

Josien van den Noort; Martin van der Esch; Martijn P. Steultjens; Joost Dekker; Martin Schepers; Peter H. Veltink; Jaap Harlaar

2011-01-01

420

Quantity versus quality of gait and quality of life in patients with osteoarthritis  

Microsoft Academic Search

Purpose: This study investigated the relationship between the quality of life, quality of gait and the quantity of gait in patients with impairments in the lower extremities. Methods: Twenty-six subjects (age 58.6 13.4 years) suffering from knee or hip osteoarthritis were investigated before implantation of an endoprosthesis. Quality of life was assessed using the SF-36 survey. The quality of gait

Mirko Brandes; Ralph Schomaker; Gunnar Mollenhoff; Dieter Rosenbaum

2007-01-01

421

The effect of insufficient quadriceps strength on gait after anterior cruciate ligament reconstruction  

Microsoft Academic Search

Objective. To determine the effect of quadriceps strength and joint stability on gait patterns after anterior cruciate ligament injury and reconstruction.Design. Cross-sectional comparative study in which four groups underwent motion analysis with surface electromyography.Background. Individuals following anterior cruciate ligament rupture often demonstrate reduced knee angles and moments during the early stance phase of gait. Alterations in gait can neither be

Michael Lewek; Katherine Rudolph; Michael Axe; Lynn Snyder-Mackler

2002-01-01

422

Trunk sway during walking among older adults: Norms and correlation with gait velocity.  

PubMed

The aim of this study was to establish quantitative norms for trunk sway during walking for older male and female ambulatory adults at different age groups (65-70, 71-75, 76-80, ?81). We also assessed the relationship between dynamic trunk sway and gait velocity in older individuals with clinically normal or abnormal gaits. Trunk sway in medio-lateral (roll) and antero-posterior (pitch) planes was measured using a body-mounted gyroscope (SwayStar) during walking on a 4.5m long instrumented walkway. Of the 284 older adults (mean age 76.8, 54.6% women) in this sample, the mean±SD value of roll and pitch angles were 6.0±2.0° and 6.7±2.2° respectively. Older women showed significantly greater trunk sway in both roll and pitch angles than older men (p<0.01). In both men and women, there was no significant association of roll angle with age although gait velocity decreased with increasing age. The relationship between roll angle and gait velocity was U-shaped for the overall sample. Among the subgroup with clinically normal gait, increased roll angle was associated with increased gait velocity (p<0.001). However, there was no significant relationship between roll angle and gait velocity among the subgroup with abnormal gait. Therefore, the relationship between medio-lateral trunk sway and gait velocity differs depending on whether gait is clinically normal. We conclude that trunk sway during walking should be interpreted with consideration of both gait velocity and presence of gait abnormality in older adults. PMID:25155693

Lee, Se Won; Verghese, Joe; Holtzer, Roee; Mahoney, Jeannette R; Oh-Park, Mooyeon

2014-09-01

423

A computational model for dynamic analysis of the human gait.  

PubMed

Biomechanical models are important tools in the study of human motion. This work proposes a computational model to analyse the dynamics of lower limb motion using a kinematic chain to represent the body segments and rotational joints linked by viscoelastic elements. The model uses anthropometric parameters, ground reaction forces and joint Cardan angles from subjects to analyse lower limb motion during the gait. The model allows evaluating these data in each body plane. Six healthy subjects walked on a treadmill to record the kinematic and kinetic data. In addition, anthropometric parameters were recorded to construct the model. The viscoelastic parameter values were fitted for the model joints (hip, knee and ankle). The proposed model demonstrated that manipulating the viscoelastic parameters between the body segments could fit the amplitudes and frequencies of motion. The data collected in this work have viscoelastic parameter values that follow a normal distribution, indicating that these values are directly related to the gait pattern. To validate the model, we used the values of the joint angles to perform a comparison between the model results and previously published data. The model results show a same pattern and range of values found in the literature for the human gait motion. PMID:24156601

Vimieiro, Claysson; Andrada, Emanuel; Witte, Hartmut; Pinotti, Marcos

2015-05-01

424

Evidence for joint moment asymmetry in healthy populations during gait.  

PubMed

The purpose of this study was to determine the presence and prevalence of asymmetry in lower extremity joint moments within and across healthy populations during overground walking. Bilateral gait data from several studies performed at two institutions were pooled from 182 healthy, pain-free subjects. Four distinct populations were identified based on age, activity level and body mass index. Mean peak external joint moments were calculated from three to six trials of level overground walking at self-selected speed for each subject. Right and left limb moments were reclassified as "greater" or "lesser" moment for each subject to prevent obscuring absolute asymmetry due to averaging over positive and negative asymmetries across subjects. A clinically relevant asymmetry measure was calculated from the peak joint moments with an initial chosen cutoff value of 10%. Confidence intervals for the proportion of subjects with greater than 10% asymmetry between limbs were estimated based on the binomial distribution. We found a high amount of asymmetry between the limbs in healthy populations. More than half of our overall population exceeded 10% asymmetry in peak hip and knee flexion and adduction moments. Group medians exceeded 10% asymmetry for all variables in all populations. This may have important implications on gait evaluations, particularly clinical evaluations or research studies where asymmetry is used as an outcome. Additional research is necessary to determine acceptable levels of joint moment asymmetry during gait and to determine whether asymmetrical joint moments influence the development of symptomatic pathology or success of lower extremity rehabilitation. PMID:25035185

Lathrop-Lambach, Rebecca L; Asay, Jessica L; Jamison, Steve T; Pan, Xueliang; Schmitt, Laura C; Blazek, Katerina; Siston, Robert A; Andriacchi, Thomas P; Chaudhari, Ajit M W

2014-09-01

425

Obstacle avoidance to elicit freezing of gait during treadmill walking.  

PubMed

Freezing of gait (FOG) is a common and disabling feature of Parkinson's disease (PD). Detailed pathophysiological studies are hampered by the fact that FOG episodes are difficult to elicit in a gait laboratory. We evaluated whether the need to avoid sudden obstacles on a treadmill can provoke FOG. We included 21 PD patients (15 with self-reported off-period FOG). Patients were tested in the off-state. FOG during overground walking was assessed using a standardized gait trajectory and axial 360 degrees turns. Subsequently, patients walked on a motorized treadmill with suddenly appearing obstacles that necessitated compensatory stepping. Performance was videotaped, and presence of FOG was scored visually by two independent raters. Thirteen patients showed FOG during overground walking. During treadmill walking, obstacle avoidance was associated with 13 unequivocal FOG episodes in eight patients, whereas only one patient froze during undisturbed treadmill walking (Wilcoxon z = -2.0, P = 0.046). FOG episodes elicited by obstacle avoidance were brief (typically <1 s). Almost all episodes were provoked when subjects had a longer available response time. In conclusion, suddenly appearing obstacles on a treadmill can elicit FOG in a controlled laboratory setting. However, the moving treadmill and the obstacle both act as cues, which apparently help to immediately overcome the provoked FOG episode. This may limit the ecological validity of this new approach. PMID:19938174

Snijders, Anke H; Weerdesteyn, Vivian; Hagen, Yolien J; Duysens, Jacques; Giladi, Nir; Bloem, Bastiaan R

2010-01-15

426

Starved bearing technology theory and experiment  

SciTech Connect

This dissertation describes using developments in free boundary problems analysis and extending them to include temperature effects in starved journal bearings. The study used bearing sizes ranging from 3 in. to 12 in. in diameter and conditions ranging from full hydrodynamic lubrication to a state of extreme lubricant starvation. The oil delivery of oil rings was experimentally determined, and the characteristics of rings through several regimes of operation were determined up to journal speeds at which the ring becomes unstable and oil delivery ceases. A parametric study of ring weight, size, shape, tooth depth and orientation, as well as ring material, yielded an optimum ring configuration from the standpoint of maximum oil delivery to the bearing. Results of an extensive series of tests showed an excellent agreement with the theory and confirmed some of the essential conclusions of the analysis, namely, that the effects of starvation accelerate below the 50% starvation line and that the start of the incomplete film depends only on the level of starvation. Noted for starved bearings was an optimum length-to-diameter ratio which is on the order of 0.6 to 0.8. The form and occurrence of cavitation, film rupture, and the cavitation in starved bearings are all determined in detail in the light of available experiments. A correlation is offered that provides an estimate of the expected mixing temperature in terms of known geometric and operational parameters.

Heshmat, H.

1988-01-01

427

The influence of body weight support on ankle mechanics during treadmill walking  

Microsoft Academic Search

The use of body weight support (BWS) systems during locomotor retraining has become routine in clinical settings. BWS alters load receptor feedback, however, and may alter the biomechanical role of the ankle plantarflexors, influencing gait. The purpose of this study was to characterize the biomechanical adaptations that occur as a result of a change in limb load (controlled indirectly through

Michael D. Lewek

2011-01-01

428

Metabolic Cost, Mechanical Work, and Efficiency during Normal Walking in Obese and Normal-Weight Children  

ERIC Educational Resources Information Center

Purpose: This study aimed to investigate the influence of childhood obesity on energetic cost during normal walking and to determine if obese children choose a walking strategy optimizing their gait pattern. Method: Sixteen obese children with no functional abnormalities were matched by age and gender with 16 normal-weight children. All…

Huang, Liang; Chen, Peijie; Zhuang, Jie; Zhang, Yanxin; Walt, Sharon

2013-01-01

429

An Ambulatory Method of Identifying Anterior Cruciate Ligament Reconstructed Gait Patterns  

PubMed Central

The use of inertial sensors to characterize pathological gait has traditionally been based on the calculation of temporal and spatial gait variables from inertial sensor data. This approach has proved successful in the identification of gait deviations in populations where substantial differences from normal gait patterns exist; such as in Parkinsonian gait. However, it is not currently clear if this approach could identify more subtle gait deviations, such as those associated with musculoskeletal injury. This study investigates whether additional analysis of inertial sensor data, based on quantification of gyroscope features of interest, would provide further discriminant capability in this regard. The tested cohort consisted of a group of anterior cruciate ligament reconstructed (ACL-R) females and a group of non-injured female controls, each performed ten walking trials. Gait performance was measured simultaneously using inertial sensors and an optoelectronic marker based system. The ACL-R group displayed kinematic and kinetic deviations from the control group, but no temporal or spatial deviations. This study demonstrates that quantification of gyroscope features can successfully identify changes associated with ACL-R gait, which was not possible using spatial or temporal variables. This finding may also have a role in other clinical applications where small gait deviations exist. PMID:24451464

Patterson, Matthew R.; Delahunt, Eamonn; Sweeney, Kevin T.; Caulfield, Brian

2014-01-01

430

Hip contact force in presence of aberrant bone geometry during normal and pathological gait.  

PubMed

Children with cerebral palsy (CP) often present aberrant hip geometry, specifically increased femoral anteversion and neck-shaft angle. Furthermore, altered gait patterns are present within this population. We analyzed the effect of aberrant femoral geometry, as present in CP subjects, on hip contact force (HCF) during pathological and normal gait. We ran dynamic simulations of CP-specific and normal gait using two musculoskeletal models (MSMs), one reflecting normal femoral geometry and one reflecting proximal femoral deformities. The combination of aberrant bone geometry and CP-specific gait characteristics reduced HCF compared to normal gait on a CP subject-specific MSM, but drastically changed the orientation of the HCF vector. The HCF was orientated more vertically and anteriorly than compared to HCF orientation during normal gait. Furthermore, subjects with more pronounced bony deformities encountered larger differences in resultant HCF and HCF orientation. When bone deformities were not accounted for in MSMs of pathologic gait, the HCF orientation was more similar to normal children. Thus, our results support a relation between aberrant femoral geometry and joint loading during pathological/normal gait and confirm a compensatory effect of altered gait kinematics on joint loading. PMID:25087777

Bosmans, Lode; Wesseling, Mariska; Desloovere, Kaat; Molenaers, Guy; Scheys, Lennart; Jonkers, Ilse

2014-11-01

431

A Comparison of Gait Kinetics between Prosthetic Feet during Functional Activities - Symmetry in External Work Approach.  

E-print Network

??Background: Unilateral transtibial amputees (TTAs) show subtle gait variations while using different prosthetic feet. These variations have not been detected consistently with previous experimental measures.… (more)

Agrawal, Vibhor

2010-01-01

432

Statistical method for prediction of gait kinematics with Gaussian process regression.  

PubMed

We propose a novel methodology for predicting human gait pattern kinematics based on a statistical and stochastic approach using a method called Gaussian process regression (GPR). We selected 14 body parameters that significantly affect the gait pattern and 14 joint motions that represent gait kinematics. The body parameter and gait kinematics data were recorded from 113 subjects by anthropometric measurements and a motion capture system. We generated a regression model with GPR for gait pattern prediction and built a stochastic function mapping from body parameters to gait kinematics based on the database and GPR, and validated the model with a cross validation method. The function can not only produce trajectories for the joint motions associated with gait kinematics, but can also estimate the associated uncertainties. Our approach results in a novel, low-cost and subject-specific method for predicting gait kinematics with only the subject's body parameters as the necessary input, and also enables a comprehensive understanding of the correlation and uncertainty between body parameters and gait kinematics. PMID:24211221

Yun, Youngmok; Kim, Hyun-Chul; Shin, Sung Yul; Lee, Junwon; Deshpande, Ashish D; Kim, Changhwan

2014-01-01

433

Alpha oscillations in the pedunculopontine nucleus correlate with gait performance in parkinsonism  

PubMed Central

The pedunculopontine nucleus, a component of the reticular formation, is topographically organized in animal models and implicated in locomotor control. In Parkinson's disease, pedunculopontine nucleus stimulation is an emerging treatment for gait freezing. Local field potentials recorded from pedunculopontine nucleus electrodes in such patients have demonstrated oscillations in the alpha and beta frequency bands, reactive to self-paced movement. Whether these oscillations are topographically organized or relevant to locomotion is unknown. Here, we recorded local field potentials from the pedunculopontine nucleus in parkinsonian patients during rest and unconstrained walking. Relative gait speed was assessed with trunk accelerometry. Peaks of alpha power were present at rest and during gait, when they correlated with gait speed. Gait freezing was associated with attenuation of alpha activity. Beta peaks were less consistently observed across rest and gait, and did not correlate with gait speed. Alpha power was maximal in the caudal pedunculopontine nucleus region and beta power was maximal rostrally. These results indicate a topographic distribution of neuronal activity in the pedunculopontine nucleus region and concur with animal data suggesting that the caudal subregion has particular relevance to gait. Alpha synchronization, proposed to suppress ‘task irrelevant’ distraction, has previously been demonstrated to correlate with performance of cognitive tasks. Here, we demonstrate a correlation between alpha oscillations and improved gait performance. The results raise the possibility that stimulation of caudal and rostral pedunculopontine nucleus regions may differ in their clinical effects. PMID:22232591

Thevathasan, Wesley; Pogosyan, Alek; Hyam, Jonathan A.; Jenkinson, Ned; Foltynie, Tom; Limousin, Patricia; Bogdanovic, Marko; Zrinzo, Ludvic; Green, Alexander L.; Aziz, Tipu Z.

2012-01-01

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An ambulatory method of identifying anterior cruciate ligament reconstructed gait patterns.  

PubMed

The use of inertial sensors to characterize pathological gait has traditionally been based on the calculation of temporal and spatial gait variables from inertial sensor data. This approach has proved successful in the identification of gait deviations in populations where substantial differences from normal gait patterns exist; such as in Parkinsonian gait. However, it is not currently clear if this approach could identify more subtle gait deviations, such as those associated with musculoskeletal injury. This study investigates whether additional analysis of inertial sensor data, based on quantification of gyroscope features of interest, would provide further discriminant capability in this regard. The tested cohort consisted of a group of anterior cruciate ligament reconstructed (ACL-R) females and a group of non-injured female controls, each performed ten walking trials. Gait performance was measured simultaneously using inertial sensors and an optoelectronic marker based system. The ACL-R group displayed kinematic and kinetic deviations from the control group, but no temporal or spatial deviations. This study demonstrates that quantification of gyroscope features can successfully identify changes associated with ACL-R gait, which was not possible using spatial or temporal variables. This finding may also have a role in other clinical applications where small gait deviations exist. PMID:24451464

Patterson, Matthew R; Delahunt, Eamonn; Sweeney, Kevin T; Caulfield, Brian

2014-01-01